fix: period close sweeps only through the period end; partnerships close into members' capital

The close zeroed every revenue and expense account's all-time movement,
so closing a period after later entries were posted swept those too:
close January in March and February's and March's income landed in
January's closing entry. The preview had the same bug and never showed
where the net went. Now:

- close_period_to(id, to) zeroes balances as of the period end; entries
  dated later stay open for their own period. Periods must close in
  order (LedgerError::CloseOutOfOrder): a later close has already swept
  the earlier period.
- CloseTo::Members: for a partnership (multi-member LLC) the net goes to
  each member's capital account by share, to the cent, the last member
  absorbing rounding, which is what K-1 capital accounts track.
  CloseTo::RetainedEarnings (3999) stays the default; close_period is
  shorthand for it. books.close_period picks Members when
  wanderbooks.toml lists members.
- The journal records the close target; replay re-derives the closing
  entry and now compares every line with the journal, not just the id,
  so a change to closing math can never silently rewrite history.
- The tool's preview is the real close run on a clone of the ledger
  (Ledger now derives Clone), so preview and post can't disagree.
- Members' equity: closing entries into a capital account are income,
  not contributions. Balance sheet for a partnership: capital accounts
  (with allocated earnings), then only unallocated earnings —
  "Undistributed earnings, prior years" if any, and this year's unclosed
  net income (loss). periods::allocate is shared by the close and the
  statement.

Tests: January closed after February is posted sweeps exactly Dr 4000
2,500 / Cr 6100 800 / Cr 3999 1,700 (mutation-checked: the old code gives
3,500/120/800/2,580); out-of-order close refused; a partnership close
splits 666.67 into 333.34/333.33 with no 3999, and the members' equity
statement reads correctly before and after; store replay of a members
close (reopen, rebuild, verify); partnership and corporate balance sheet
layouts; stdio close preview equals the posted lines.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MtYEaR6M6Ybdhm6X98BWNu

crates/ledger-core/src/error.rs

@@ -166,6 +166,10 @@ pub enum LedgerError {
     #[error("cannot close period {0}: draft entries exist with dates in the period")]
     DraftsInPeriod(u64),
 
+    /// A period can't close while a later period is already closed.
+    #[error("period {0} can't close: later period {1} is already closed (close in order)")]
+    CloseOutOfOrder(u64, u64),
+
     /// Entries cannot be created or posted in a closed period.
     #[error("period {0} is closed; entries dated {1} are rejected")]
     ClosedPeriod(u64, String),

crates/ledger-core/src/ledger.rs

@@ -57,7 +57,7 @@ pub struct ReconciliationReport {
 }
 
 /// The books. Single-currency (see R-5); owns id allocation.
-#[derive(Debug)]
+#[derive(Clone, Debug)]
 pub struct Ledger {
     base_currency: Currency,
     chart: ChartOfAccounts,
@@ -587,42 +587,49 @@ impl Ledger {
             .collect()
     }
 
-    /// Close a period. This:
-    /// 1. Rejects if the period is already closed.
-    /// 2. Rejects if any draft entries have dates inside the period.
-    /// 3. Posts a closing entry dated at period end: revenue accounts are
-    ///    debited to zero, expense accounts are credited to zero, and the
-    ///    net goes to Retained Earnings (account `3999`, created if missing).
-    /// 4. Marks the period closed.
-    ///
-    /// Returns the closing entry's id, or `None` if there was nothing to
-    /// close (no revenue/expense movement).
+    /// Close a period into Retained Earnings: see [`Self::close_period_to`].
     pub fn close_period(&mut self, id: PeriodId) -> Result<Option<EntryId>, LedgerError> {
-        let period = self
-            .periods
-            .get(&id)
-            .ok_or(LedgerError::UnknownPeriod(id))?
-            .clone();
-        if period.status == PeriodStatus::Closed {
-            return Err(LedgerError::PeriodAlreadyClosed(id));
-        }
-        // No drafts may have dates inside the period.
-        let has_drafts = self
-            .entries
-            .values()
-            .any(|e| e.status() == EntryStatus::Draft && period.contains(e.date()));
-        if has_drafts {
-            return Err(LedgerError::DraftsInPeriod(id));
+        self.close_period_to(id, &periods::CloseTo::RetainedEarnings)
     }
 
-        // Collect revenue and expense accounts with non-zero movement.
+    /// Close a period. This:
+    /// 1. Rejects if the period is already closed, if any draft is dated
+    ///    inside it, or if a later period is already closed (closing out of
+    ///    order would sweep the same income twice).
+    /// 2. Posts a closing entry dated at period end that zeroes every revenue
+    ///    and expense account's balance *as of the period end* (entries
+    ///    dated after it stay open for their own period): revenue debited,
+    ///    expense credited, and the net to `to` — Retained Earnings (account
+    ///    `3999`, created if missing), or members' capital accounts by
+    ///    share for a partnership, to the cent with the last member
+    ///    absorbing rounding.
+    /// 3. Marks the period closed.
+    ///
+    /// Returns the closing entry's id, or `None` if there was nothing to
+    /// close (no revenue/expense balance at period end).
+    pub fn close_period_to(
+        &mut self,
+        id: PeriodId,
+        to: &periods::CloseTo,
+    ) -> Result<Option<EntryId>, LedgerError> {
+        self.preview_close_period(id)?;
+        if let periods::CloseTo::Members(members) = to {
+            self.validate_close_members(members)?;
+        }
+        let period = self.periods.get(&id).expect("previewed").clone();
+
+        // Revenue and expense balances as of the period end.
         let mut closings: Vec<(AccountId, Side, Decimal)> = Vec::new();
         let mut accounts: Vec<_> = self.chart.all().collect();
         accounts.sort_by(|a, b| a.code.cmp(&b.code));
         for account in accounts {
-            match account.account_type {
-                AccountType::Revenue | AccountType::Expense => {
-                    let movement = self.account_movement(account.id);
+            if !matches!(
+                account.account_type,
+                AccountType::Revenue | AccountType::Expense
+            ) {
+                continue;
+            }
+            let movement = self.movement_through(account.id, period.end);
             if movement.is_zero() {
                 continue;
             }
@@ -634,14 +641,20 @@ impl Ledger {
             };
             closings.push((account.id, side, amount));
         }
-                _ => {}
-            }
-        }
 
         let closing_entry = if closings.is_empty() {
             None
         } else {
-            // Ensure Retained Earnings exists.
+            // Net income: the closing debits (revenue) minus credits (expense).
+            let net: Decimal = closings
+                .iter()
+                .map(|(_, side, amount)| match side {
+                    Side::Debit => *amount,
+                    Side::Credit => -*amount,
+                })
+                .sum();
+            let targets: Vec<(AccountId, Decimal)> = match to {
+                periods::CloseTo::RetainedEarnings => {
                     let re_id = match self.chart.find_by_code(periods::RETAINED_EARNINGS_CODE) {
                         Some(a) => a.id,
                         None => self.add_account(
@@ -652,49 +665,83 @@ impl Ledger {
                             false,
                         )?,
                     };
-            // Sum the closing lines to find the net for RE.
-            let mut debits = Decimal::ZERO;
-            let mut credits = Decimal::ZERO;
-            for (_, side, amount) in &closings {
-                match side {
-                    Side::Debit => debits += *amount,
-                    Side::Credit => credits += *amount,
+                    vec![(re_id, net)]
                 }
+                periods::CloseTo::Members(members) => {
+                    let shares: Vec<Decimal> = members.iter().map(|(_, s)| *s).collect();
+                    members
+                        .iter()
+                        .map(|(a, _)| *a)
+                        .zip(periods::allocate(net, &shares))
+                        .collect()
                 }
+            };
             let entry = self.create_entry(period.end, &format!("Close period {}", period.name));
             for (account, side, amount) in closings {
                 self.add_line(entry, account, side, Money::new(amount, self.base_currency))?;
             }
-            // Balance with Retained Earnings.
-            if debits > credits {
-                // Profit: credit RE.
-                self.add_line(
-                    entry,
-                    re_id,
-                    Side::Credit,
-                    Money::new(debits - credits, self.base_currency),
-                )?;
-            } else if credits > debits {
-                // Loss: debit RE.
-                self.add_line(
-                    entry,
-                    re_id,
-                    Side::Debit,
-                    Money::new(credits - debits, self.base_currency),
-                )?;
+            // Profit credits equity; a loss debits it.
+            for (account, share) in targets {
+                if share.is_zero() {
+                    continue;
+                }
+                let (side, amount) = if share > Decimal::ZERO {
+                    (Side::Credit, share)
+                } else {
+                    (Side::Debit, -share)
+                };
+                self.add_line(entry, account, side, Money::new(amount, self.base_currency))?;
             }
             self.post_entry(entry)?;
             Some(entry)
         };
 
-        self.periods.get_mut(&id).expect("period exists").status = PeriodStatus::Closed;
-        self.periods
-            .get_mut(&id)
-            .expect("period exists")
-            .closing_entry = closing_entry;
+        let p = self.periods.get_mut(&id).expect("period exists");
+        p.status = PeriodStatus::Closed;
+        p.closing_entry = closing_entry;
         Ok(closing_entry)
     }
 
+    /// Members for a close: shares positive and summing to 1, capital
+    /// accounts distinct equity accounts.
+    fn validate_close_members(&self, members: &[(AccountId, Decimal)]) -> Result<(), LedgerError> {
+        let total: Decimal = members.iter().map(|(_, s)| *s).sum();
+        if members.is_empty()
+            || total != Decimal::ONE
+            || members.iter().any(|(_, s)| *s <= Decimal::ZERO)
+        {
+            return Err(LedgerError::InvalidMembers(format!(
+                "member shares must be positive and sum to 1, got {total}"
+            )));
+        }
+        let mut seen = std::collections::BTreeSet::new();
+        for (a, _) in members {
+            let account = self.chart.get(*a).ok_or(LedgerError::UnknownAccount(*a))?;
+            if account.account_type != AccountType::Equity || !seen.insert(*a) {
+                return Err(LedgerError::InvalidMembers(format!(
+                    "capital account {} must be a distinct equity account",
+                    account.code
+                )));
+            }
+        }
+        Ok(())
+    }
+
+    /// Debits minus credits on an account across posted entries dated on or
+    /// before `end`.
+    fn movement_through(&self, account: AccountId, end: NaiveDate) -> Decimal {
+        let mut total = Decimal::ZERO;
+        for entry in self.posted_entries().filter(|e| e.date() <= end) {
+            for line in entry.lines().iter().filter(|l| l.account == account) {
+                match line.side {
+                    Side::Debit => total += line.amount.amount,
+                    Side::Credit => total -= line.amount.amount,
+                }
+            }
+        }
+        total
+    }
+
     /// Pure pre-close check for journaling stores: verifies that
     /// [`Self::close_period`] would succeed — the period exists and is open,
     /// no draft entries are dated inside it, and the closing entry's date
@@ -724,14 +771,23 @@ impl Ledger {
         {
             return Err(LedgerError::ClosedPeriod(other, period.end.to_string()));
         }
+        // Periods close in order: a later closed period already swept this
+        // one's income, so closing it now would sweep it again.
+        if let Some(later) = self
+            .periods
+            .values()
+            .find(|p| p.status == PeriodStatus::Closed && p.end > period.end)
+        {
+            return Err(LedgerError::CloseOutOfOrder(id, later.id));
+        }
         // The close posts an entry exactly when some revenue or expense
-        // account has non-zero movement — the same predicate close_period
-        // uses to decide. The entry id is the next one the allocator hands
-        // out; account creation (e.g. Retained Earnings) does not consume
-        // entry ids.
+        // account has a balance at period end — the same predicate
+        // close_period_to uses to decide. The entry id is the next one the
+        // allocator hands out; account creation (e.g. Retained Earnings)
+        // does not consume entry ids.
         let any_movement = self.chart.all().any(|a| {
             matches!(a.account_type, AccountType::Revenue | AccountType::Expense)
-                && !self.account_movement(a.id).is_zero()
+                && !self.movement_through(a.id, period.end).is_zero()
         });
         Ok(any_movement.then_some(self.next_entry_id))
     }

crates/ledger-core/src/lib.rs

@@ -43,7 +43,7 @@ pub use journal::{EntryId, EntryStatus, JournalEntry, JournalLine};
 pub use ledger::{Ledger, ReconciliationReport, UnclearedLine};
 pub use money::{Currency, Money};
 pub use payroll::{PayrollLine, PayrollRun, PayrollRunId};
-pub use periods::{Period, PeriodId, PeriodStatus, RETAINED_EARNINGS_CODE};
+pub use periods::{CloseTo, Period, PeriodId, PeriodStatus, RETAINED_EARNINGS_CODE};
 pub use reports::{
     BalanceSheet, BalanceSheetStatement, CashFlowLine, CashFlowParams, CashFlowStatement,
     ClassProfitAndLoss, GeneralLedger, LedgerAccount, LedgerPosting, MemberCapital,

crates/ledger-core/src/periods.rs

@@ -29,6 +29,35 @@ pub enum PeriodStatus {
     Closed,
 }
 
+/// Where a period close puts the period's net income.
+#[derive(Clone, Debug, PartialEq)]
+pub enum CloseTo {
+    /// One Retained Earnings account ([`RETAINED_EARNINGS_CODE`]): the
+    /// corporate convention.
+    RetainedEarnings,
+    /// Members' capital accounts, by share (shares sum to 1): the
+    /// partnership convention, where each member's capital account carries
+    /// their allocated earnings.
+    Members(Vec<(crate::AccountId, rust_decimal::Decimal)>),
+}
+
+/// Split `amount` by `shares` to the cent; the last share absorbs rounding,
+/// so the parts always sum to `amount` exactly.
+pub fn allocate(
+    amount: rust_decimal::Decimal,
+    shares: &[rust_decimal::Decimal],
+) -> Vec<rust_decimal::Decimal> {
+    use rust_decimal::RoundingStrategy::MidpointAwayFromZero;
+    let mut parts: Vec<_> = shares
+        .iter()
+        .map(|s| (amount * s).round_dp_with_strategy(2, MidpointAwayFromZero))
+        .collect();
+    if let Some((last, rest)) = parts.split_last_mut() {
+        *last = amount - rest.iter().copied().sum::<rust_decimal::Decimal>();
+    }
+    parts
+}
+
 /// Code of the Retained Earnings account that closing entries credit (or
 /// debit), created on the first close if the chart lacks it.
 pub const RETAINED_EARNINGS_CODE: &str = "3999";

crates/ledger-core/src/reports.rs

@@ -4,6 +4,7 @@
 //! (`docs/oracle.md`) diffs: the same fixture books through two engines must
 //! produce byte-identical [`snapshot`] output.
 
+use crate::periods::allocate;
 use crate::{AccountType, Class, ClassId, JournalEntry, JournalLine, Ledger, LedgerError};
 use chrono::NaiveDate;
 use rust_decimal::Decimal;
@@ -711,20 +712,6 @@ pub struct MembersEquityStatement {
     pub total: MemberEquityColumn,
 }
 
-/// Split `amount` by `shares` to the cent; the last share absorbs rounding,
-/// so the parts always sum to `amount` exactly.
-fn allocate(amount: Decimal, shares: &[Decimal]) -> Vec<Decimal> {
-    use rust_decimal::RoundingStrategy::MidpointAwayFromZero;
-    let mut parts: Vec<Decimal> = shares
-        .iter()
-        .map(|s| (amount * s).round_dp_with_strategy(2, MidpointAwayFromZero))
-        .collect();
-    if let Some((last, rest)) = parts.split_last_mut() {
-        *last = amount - rest.iter().sum::<Decimal>();
-    }
-    parts
-}
-
 /// Build the statement of changes in members' equity for `[start, end]`.
 ///
 /// Each member's capital account supplies contributions (credits) and
@@ -783,11 +770,14 @@ pub fn members_equity(
         }
         m
     };
+    // Contributions and distributions move a capital account; a closing
+    // entry allocating earnings into it is income, already counted below.
+    let closings = ledger.closing_entry_ids();
     let flows = |id: crate::AccountId| -> (Decimal, Decimal) {
         let (mut credits, mut debits) = (Decimal::ZERO, Decimal::ZERO);
         for e in ledger
             .posted_entries()
-            .filter(|e| e.date() >= start && e.date() <= end)
+            .filter(|e| e.date() >= start && e.date() <= end && !closings.contains(&e.id()))
         {
             for l in e.lines().iter().filter(|l| l.account == id) {
                 match l.side {

crates/ledger-core/tests/statements.rs

@@ -533,3 +533,135 @@ fn cash_flow_lines_name_their_account() {
     let accounts: Vec<Option<&str>> = cf.financing.iter().map(|f| f.account.as_deref()).collect();
     assert_eq!(accounts, [Some("3000"), Some("3001")]);
 }
+
+#[test]
+fn a_close_sweeps_only_through_the_period_end() {
+    // February is already posted when January closes: the close must take
+    // January's 2,500 revenue and 800 rent (net 1,700) and leave
+    // February's 1,000 revenue and 120 software open.
+    let mut b = books(false);
+    let jan = b
+        .ledger
+        .create_period("2026-01", d(1, 1), d(1, 31))
+        .unwrap();
+    let closing = b.ledger.close_period(jan).unwrap().unwrap();
+    let lines: Vec<(String, Side, Decimal)> = b
+        .ledger
+        .get_entry(closing)
+        .unwrap()
+        .lines()
+        .iter()
+        .map(|l| {
+            (
+                b.ledger.chart().get(l.account).unwrap().code.clone(),
+                l.side,
+                l.amount.amount,
+            )
+        })
+        .collect();
+    assert_eq!(
+        lines,
+        [
+            ("4000".to_string(), Side::Debit, dec(2_500)),
+            ("6100".to_string(), Side::Credit, dec(800)),
+            ("3999".to_string(), Side::Credit, dec(1_700)),
+        ]
+    );
+    let feb = profit_and_loss_for_period(&b.ledger, d(2, 1), d(2, 28), None).unwrap();
+    assert_eq!(feb.net_income(), dec(880));
+    let bs = balance_sheet_as_of(&b.ledger, d(2, 28)).unwrap();
+    assert_eq!(bs.current_earnings, dec(880));
+    assert_eq!(
+        bs.equity.last().unwrap(),
+        &line("3999", "Retained Earnings", 1_700)
+    );
+    assert!(bs.balanced());
+}
+
+#[test]
+fn periods_close_in_order() {
+    let mut b = books(false);
+    let jan = b
+        .ledger
+        .create_period("2026-01", d(1, 1), d(1, 31))
+        .unwrap();
+    let feb = b
+        .ledger
+        .create_period("2026-02", d(2, 1), d(2, 28))
+        .unwrap();
+    b.ledger.close_period(feb).unwrap();
+    // February swept everything through Feb 28, January included.
+    assert!(matches!(
+        b.ledger.close_period(jan),
+        Err(LedgerError::CloseOutOfOrder(j, f)) if j == jan && f == feb
+    ));
+}
+
+#[test]
+fn a_partnership_closes_into_members_capital() {
+    let (mut l, members) = partnership(false);
+    let to = ledger_core::CloseTo::Members(
+        members
+            .iter()
+            .map(|m| (m.capital_account, m.share))
+            .collect(),
+    );
+    let jan = l.create_period("2026-01", d(1, 1), d(1, 31)).unwrap();
+    l.close_period_to(jan, &to).unwrap();
+    // January earned 666.67: Alice's capital gets 333.34, Bob's 333.33,
+    // and there is no Retained Earnings account at all.
+    assert!(l.chart().find_by_code("3999").is_none());
+    let bs = balance_sheet_as_of(&l, d(1, 31)).unwrap();
+    let capital: Vec<Decimal> = bs.equity.iter().map(|e| e.amount).collect();
+    assert_eq!(capital, [cents("933.34"), cents("733.33")]);
+    assert_eq!(bs.current_earnings, Decimal::ZERO);
+
+    // The statement still reads: contributions are contributions (the
+    // close is income, not a contribution), and February starts where
+    // January ended.
+    let row = |c: &ledger_core::MemberEquityColumn| {
+        (
+            c.beginning,
+            c.contributions,
+            c.net_income,
+            c.distributions,
+            c.ending,
+        )
+    };
+    let jan_me = members_equity(&l, d(1, 1), d(1, 31), &members).unwrap();
+    assert_eq!(
+        row(&jan_me.members[0]),
+        (
+            cents("0"),
+            cents("600"),
+            cents("333.34"),
+            cents("0"),
+            cents("933.34")
+        )
+    );
+    assert_eq!(
+        row(&jan_me.members[1]),
+        (
+            cents("0"),
+            cents("400"),
+            cents("333.33"),
+            cents("0"),
+            cents("733.33")
+        )
+    );
+    let feb_me = members_equity(&l, d(2, 1), d(2, 28), &members).unwrap();
+    assert_eq!(feb_me.members[0].beginning, cents("933.34"));
+    assert_eq!(feb_me.members[1].ending, cents("683.33"));
+    assert_eq!(
+        feb_me.total.ending,
+        balance_sheet_as_of(&l, d(2, 28)).unwrap().total_equity
+    );
+
+    // Shares must still add up.
+    let feb = l.create_period("2026-02", d(2, 1), d(2, 28)).unwrap();
+    let bad = ledger_core::CloseTo::Members(vec![(members[0].capital_account, cents("0.5"))]);
+    assert!(matches!(
+        l.close_period_to(feb, &bad),
+        Err(LedgerError::InvalidMembers(_))
+    ));
+}

crates/ledger-import/src/lib.rs

@@ -20,5 +20,5 @@ pub use bank_csv::{BankTransaction, parse_bank_csv};
 pub use chart_csv::{ChartRow, parse_chart_csv};
 pub use iif::{IifEntry, journal_to_iif};
 pub use pdf::{PdfError, statement_pdf};
-pub use report::{Member, ReportMeta, Row, RowKind, Statement, format_amount};
+pub use report::{Member, ReportMeta, Row, RowKind, Statement, YearEarnings, format_amount};
 pub use xlsx::{XlsxReport, report_to_xlsx};

crates/ledger-import/src/report.rs

@@ -175,14 +175,29 @@ pub fn profit_and_loss(pl: &ProfitAndLossStatement) -> Statement {
     )
 }
 
-/// Lay out a balance sheet. `net_income_ytd` is the fiscal year to date's
-/// net income (loss): it shows as its own equity line, and earnings from
-/// before the fiscal year — the Retained Earnings account plus any not yet
-/// closed — show as "Retained earnings". With `members`, equity is
-/// "Members' equity".
+/// The fiscal year's earnings, as the balance sheet presents them.
+#[derive(Clone, Copy, Debug)]
+pub struct YearEarnings {
+    /// Net income (loss) for the fiscal year through the as-of date.
+    pub net_income_ytd: Decimal,
+    /// The part of it not yet closed into equity accounts.
+    pub unclosed: Decimal,
+}
+
+/// Lay out a balance sheet.
+///
+/// Without members (corporate convention), equity ends with "Retained
+/// earnings" — the Retained Earnings account plus earlier years' earnings
+/// not yet closed — and the fiscal year's "Net income (loss)".
+///
+/// With members (a partnership), each member's capital account already
+/// carries the earnings closed into it, so equity ends with only what
+/// hasn't been allocated: "Undistributed earnings, prior years" (if any)
+/// and this year's unclosed "Net income (loss)". Equity is "Members'
+/// equity".
 pub fn balance_sheet(
     bs: &BalanceSheetStatement,
-    net_income_ytd: Decimal,
+    earnings: YearEarnings,
     members: &[Member],
 ) -> Statement {
     let equity_name = if members.is_empty() {
@@ -203,6 +218,7 @@ pub fn balance_sheet(
     ));
     rows.push(spacer());
     rows.push(section(equity_name));
+    if members.is_empty() {
         let (retained, other): (Vec<_>, Vec<_>) = bs
             .equity
             .iter()
@@ -212,12 +228,29 @@ pub fn balance_sheet(
                 .iter()
                 .map(|l| one(RowKind::Line, format!("{} {}", l.code, l.name), l.amount)),
         );
-    let retained: Decimal =
-        retained.iter().map(|l| l.amount).sum::<Decimal>() + bs.current_earnings - net_income_ytd;
+        let retained: Decimal = retained.iter().map(|l| l.amount).sum::<Decimal>()
+            + bs.current_earnings
+            - earnings.net_income_ytd;
         if !retained.is_zero() {
             rows.push(one(RowKind::Line, "Retained earnings", retained));
         }
-    rows.push(one(RowKind::Line, "Net income (loss)", net_income_ytd));
+        rows.push(one(
+            RowKind::Line,
+            "Net income (loss)",
+            earnings.net_income_ytd,
+        ));
+    } else {
+        rows.extend(account_lines(&bs.equity));
+        let prior = bs.current_earnings - earnings.unclosed;
+        if !prior.is_zero() {
+            rows.push(one(
+                RowKind::Line,
+                "Undistributed earnings, prior years",
+                prior,
+            ));
+        }
+        rows.push(one(RowKind::Line, "Net income (loss)", earnings.unclosed));
+    }
     rows.push(one(
         RowKind::Subtotal,
         format!("Total {}", equity_name.to_lowercase()),
@@ -474,50 +507,105 @@ mod tests {
         );
     }
 
-    #[test]
-    fn balance_sheet_splits_retained_earnings_from_this_year() {
-        let line = |code: &str, name: &str, a: &str| StatementLine {
+    fn sl(code: &str, name: &str, a: &str) -> StatementLine {
+        StatementLine {
             code: code.into(),
             name: name.into(),
             amount: dec(a),
-        };
+        }
+    }
+
+    fn equity_rows(st: &Statement, from: &str) -> Vec<(String, Option<Decimal>)> {
+        st.rows
+            .iter()
+            .skip_while(|r| r.label != from)
+            .map(|r| (r.label.clone(), r.amounts.first().copied().flatten()))
+            .collect()
+    }
+
+    #[test]
+    fn corporate_balance_sheet_splits_retained_earnings_from_this_year() {
         // Prior years closed 1,000 to Retained Earnings; 200 more unclosed
         // from last year; this year's net income is 300 (current earnings
         // 500 = 200 + 300).
         let bs = BalanceSheetStatement {
             as_of: NaiveDate::from_ymd_opt(2027, 3, 31).unwrap(),
-            assets: vec![line("1000", "Cash", "2500")],
+            assets: vec![sl("1000", "Cash", "2500")],
             liabilities: vec![],
             equity: vec![
-                line("3000", "Capital — Alice", "1000"),
-                line("3999", "Retained Earnings", "1000"),
+                sl("3000", "Common Stock", "1000"),
+                sl("3999", "Retained Earnings", "1000"),
             ],
             current_earnings: dec("500"),
             total_assets: dec("2500"),
             total_liabilities: dec("0"),
             total_equity: dec("2500"),
         };
-        let members = [Member {
+        let e = YearEarnings {
+            net_income_ytd: dec("300"),
+            unclosed: dec("300"),
+        };
+        let st = balance_sheet(&bs, e, &[]);
+        let some = |s: &str| Some(dec(s));
+        assert_eq!(
+            equity_rows(&st, "Equity"),
+            [
+                ("Equity".into(), None),
+                ("3000 Common Stock".into(), some("1000")),
+                ("Retained earnings".into(), some("1200")),
+                ("Net income (loss)".into(), some("300")),
+                ("Total equity".into(), some("2500")),
+                ("".into(), None),
+                ("Total liabilities and equity".into(), some("2500")),
+            ]
+        );
+    }
+
+    #[test]
+    fn partnership_balance_sheet_shows_only_unallocated_earnings() {
+        // January (100) was closed into the capital accounts; February and
+        // March (200) are this year's unclosed income; 50 from last year
+        // was never closed.
+        let bs = BalanceSheetStatement {
+            as_of: NaiveDate::from_ymd_opt(2027, 3, 31).unwrap(),
+            assets: vec![sl("1000", "Cash", "1350")],
+            liabilities: vec![],
+            equity: vec![
+                sl("3000", "Capital — Alice", "550"),
+                sl("3001", "Capital — Bob", "550"),
+            ],
+            current_earnings: dec("250"),
+            total_assets: dec("1350"),
+            total_liabilities: dec("0"),
+            total_equity: dec("1350"),
+        };
+        let e = YearEarnings {
+            net_income_ytd: dec("300"),
+            unclosed: dec("200"),
+        };
+        let members = [
+            Member {
                 name: "Alice".into(),
                 capital_code: "3000".into(),
-        }];
-        let st = balance_sheet(&bs, dec("300"), &members);
-        let eq: Vec<(&str, Option<Decimal>)> = st
-            .rows
-            .iter()
-            .skip_while(|r| r.label != "Members' equity")
-            .map(|r| (r.label.as_str(), r.amounts.first().copied().flatten()))
-            .collect();
+            },
+            Member {
+                name: "Bob".into(),
+                capital_code: "3001".into(),
+            },
+        ];
+        let st = balance_sheet(&bs, e, &members);
+        let some = |s: &str| Some(dec(s));
         assert_eq!(
-            eq,
+            equity_rows(&st, "Members' equity"),
             [
-                ("Members' equity", None),
-                ("3000 Capital — Alice", Some(dec("1000"))),
-                ("Retained earnings", Some(dec("1200"))),
-                ("Net income (loss)", Some(dec("300"))),
-                ("Total members' equity", Some(dec("2500"))),
-                ("", None),
-                ("Total liabilities and members' equity", Some(dec("2500"))),
+                ("Members' equity".into(), None),
+                ("3000 Capital — Alice".into(), some("550")),
+                ("3001 Capital — Bob".into(), some("550")),
+                ("Undistributed earnings, prior years".into(), some("50")),
+                ("Net income (loss)".into(), some("200")),
+                ("Total members' equity".into(), some("1350")),
+                ("".into(), None),
+                ("Total liabilities and members' equity".into(), some("1350")),
             ]
         );
     }

crates/ledger-mcp/src/server.rs

@@ -117,14 +117,31 @@ impl BooksServer {
             .collect()
     }
 
-    /// Net income (loss) for the fiscal year containing `as_of`, through it.
-    fn net_income_ytd(&self, ledger: &Ledger, as_of: NaiveDate) -> Result<Decimal, String> {
+    /// The fiscal year's earnings through `as_of`, for the balance sheet:
+    /// net income (loss) year to date (closing entries excluded), and the
+    /// part of it still unclosed (closing entries included, so months
+    /// already closed into equity drop out).
+    fn year_earnings(
+        &self,
+        ledger: &Ledger,
+        as_of: NaiveDate,
+    ) -> Result<ledger_import::YearEarnings, String> {
         let (fy_start, _) = self.company.fiscal_year_containing(as_of);
-        Ok(
-            ledger_core::profit_and_loss_for_period(ledger, fy_start, as_of, None)
+        let net_income_ytd = ledger_core::profit_and_loss_for_period(ledger, fy_start, as_of, None)
             .map_err(|e| e.to_string())?
-                .net_income(),
-        )
+            .net_income();
+        let mut unclosed = Decimal::ZERO;
+        for a in ledger.chart().all().filter(|a| !a.placeholder) {
+            match a.account_type {
+                AccountType::Revenue => unclosed += movement_in(ledger, a.id, fy_start, as_of),
+                AccountType::Expense => unclosed -= movement_in(ledger, a.id, fy_start, as_of),
+                _ => {}
+            }
+        }
+        Ok(ledger_import::YearEarnings {
+            net_income_ytd,
+            unclosed,
+        })
     }
 
     fn lock(&self) -> Result<std::sync::MutexGuard<'_, Store>, String> {
@@ -1529,8 +1546,8 @@ impl BooksServer {
             )?),
             "balance_sheet" => {
                 let bs = bs_statement(ledger, p.as_of.as_deref())?;
-                let ytd = self.net_income_ytd(ledger, bs.as_of)?;
-                report::balance_sheet(&bs, ytd, &members)
+                let earnings = self.year_earnings(ledger, bs.as_of)?;
+                report::balance_sheet(&bs, earnings, &members)
             }
             "cash_flow" => report::cash_flow(
                 &cash_flow_statement(
@@ -1952,7 +1969,7 @@ impl BooksServer {
 
     #[tool(
         name = "books.close_period",
-        description = "Close an accounting period. Without confirmed=true, returns a preview of the closing entry (revenue/expense zeroed to Retained Earnings) and closes nothing. With confirmed=true, posts the closing entry and marks the period closed. Closed periods reject new entries."
+        description = "Close an accounting period. The closing entry, dated at period end, zeroes revenue and expense balances as of that date into Retained Earnings, or, for a multi-member LLC (members in wanderbooks.toml), into each member's capital account by share. Periods close in order. Without confirmed=true, returns the exact closing entry it would post and closes nothing. With confirmed=true, posts it and marks the period closed. Closed periods reject new entries."
     )]
     async fn close_period(
         &self,
@@ -1964,53 +1981,53 @@ impl BooksServer {
         if store.ledger().get_period(p.period_id).is_none() {
             return Err(format!("unknown period {}", p.period_id));
         }
-        if !p.confirmed {
-            // Preview: compute what the closing entry would look like
-            // without mutating. We do this by inspecting revenue/expense
-            // balances directly.
-            let mut lines = Vec::new();
-            let mut accounts: Vec<_> = store.ledger().chart().all().collect();
-            accounts.sort_by(|a, b| a.code.cmp(&b.code));
-            for account in accounts {
-                match account.account_type {
-                    AccountType::Revenue | AccountType::Expense => {
-                        let movement = store.ledger().account_movement(account.id);
-                        if movement.is_zero() {
-                            continue;
-                        }
-                        let (side, amount) = if movement > Decimal::ZERO {
-                            ("credit", movement)
+        // A partnership closes into its members' capital accounts by share;
+        // everyone else into Retained Earnings.
+        let to = if self.company.members.is_empty() {
+            ledger_core::CloseTo::RetainedEarnings
         } else {
-                            ("debit", -movement)
+            ledger_core::CloseTo::Members(
+                self.member_capitals(store.ledger())?
+                    .into_iter()
+                    .map(|m| (m.capital_account, m.share))
+                    .collect(),
+            )
         };
-                        lines.push(format!("{} {} {} to zero", side, account.code, amount));
-                    }
-                    _ => {}
-                }
-            }
-            return Ok(Json(ClosePeriodOut {
-                status: "preview".to_string(),
-                period_id: p.period_id,
-                closing_entry: None,
-                lines,
-            }));
-        }
-        let closing = store.close_period(p.period_id).map_err(|e| e.to_string())?;
-        // Build line descriptions from the posted closing entry.
-        let mut lines = Vec::new();
-        if let Some(eid) = closing
-            && let Some(entry) = store.ledger().get_entry(eid)
-        {
-            for line in entry.lines() {
-                let code = store
-                    .ledger()
+        let describe = |ledger: &Ledger, eid: Option<ledger_core::EntryId>| -> Vec<String> {
+            let Some(entry) = eid.and_then(|e| ledger.get_entry(e)) else {
+                return Vec::new();
+            };
+            entry
+                .lines()
+                .iter()
+                .map(|line| {
+                    let code = ledger
                         .chart()
                         .get(line.account)
                         .map(|a| a.code.clone())
                         .unwrap_or_default();
-                lines.push(format!("{:?} {} {}", line.side, code, line.amount.amount));
-            }
+                    format!("{:?} {} {}", line.side, code, money(line.amount.amount))
+                })
+                .collect()
+        };
+        if !p.confirmed {
+            // Preview: run the real close on a copy of the ledger, so the
+            // preview is exactly what confirming would post.
+            let mut scratch = store.ledger().clone();
+            let closing = scratch
+                .close_period_to(p.period_id, &to)
+                .map_err(|e| e.to_string())?;
+            return Ok(Json(ClosePeriodOut {
+                status: "preview".to_string(),
+                period_id: p.period_id,
+                closing_entry: None,
+                lines: describe(&scratch, closing),
+            }));
         }
+        let closing = store
+            .close_period_to(p.period_id, &to)
+            .map_err(|e| e.to_string())?;
+        let lines = describe(store.ledger(), closing);
         Ok(Json(ClosePeriodOut {
             status: "closed".to_string(),
             period_id: p.period_id,
@@ -2644,7 +2661,7 @@ impl BooksServer {
                 "balance-sheet",
                 report::balance_sheet(
                     &bs_statement(ledger, Some(&as_of_s))?,
-                    self.net_income_ytd(ledger, as_of)?,
+                    self.year_earnings(ledger, as_of)?,
                     &members,
                 ),
             ),

crates/ledger-mcp/tests/mcp_stdio.rs

@@ -1022,4 +1022,37 @@ fn mcp_period_statements_over_stdio() {
         json!({"format": "pdf", "report": "members_equity", "end": "2026-02-28"}),
     );
     assert_eq!(pdf["content_encoding"], "base64");
+
+    // Closing January: a one-member LLC closes into the member's capital
+    // account, not Retained Earnings. The preview is exactly what posts.
+    let jan = mcp.call(
+        "books.create_period",
+        json!({"name": "2026-01", "start": "2026-01-01", "end": "2026-01-31"}),
+    );
+    let jan_id = jan["period_id"].as_u64().unwrap();
+    let preview = mcp.call(
+        "books.close_period",
+        json!({"period_id": jan_id, "confirmed": false}),
+    );
+    assert_eq!(
+        preview["lines"],
+        json!(["Debit 4000 4.00", "Credit 3000 4.00"])
+    );
+    let closed = mcp.call(
+        "books.close_period",
+        json!({"period_id": jan_id, "confirmed": true}),
+    );
+    assert_eq!(closed["lines"], preview["lines"]);
+    let jan_bs = mcp.call("books.balance_sheet", json!({"as_of": "2026-01-31"}));
+    assert_eq!(jan_bs["equity_accounts"][0]["amount"], "1004.00");
+    assert_eq!(jan_bs["current_earnings"], "0.00");
+    // The close is income, not a contribution.
+    let me = mcp.call(
+        "books.export",
+        json!({"format": "json", "report": "members_equity", "start": "2026-01-01", "end": "2026-01-31"}),
+    );
+    let me: serde_json::Value = serde_json::from_str(me["content"].as_str().unwrap()).unwrap();
+    assert_eq!(me["total"]["contributions"], "1000.00");
+    assert_eq!(me["total"]["net_income"], "4.00");
+    assert_eq!(me["total"]["ending"], "1004.00");
 }

crates/ledger-store/src/store.rs

@@ -12,9 +12,9 @@ use crate::journal::{JournalLine, JournalWriter, read_and_verify_journal};
 use crate::schema;
 use chrono::{Months, NaiveDate};
 use ledger_core::{
-    AccountId, AccountType, AssetId, AssetStatus, BillId, Class, ClassId, Currency, CustomerId,
-    DocumentLine, EntryId, EntryStatus, InvoiceId, Ledger, LedgerError, Money, NewAsset,
-    PayrollLine, PayrollRun, PayrollRunId, PeriodId, Side, VendorId, arap,
+    AccountId, AccountType, AssetId, AssetStatus, BillId, Class, ClassId, CloseTo, Currency,
+    CustomerId, DocumentLine, EntryId, EntryStatus, InvoiceId, Ledger, LedgerError, Money,
+    NewAsset, PayrollLine, PayrollRun, PayrollRunId, PeriodId, Side, VendorId, arap,
     payroll::{PayrollAccounts, payroll_entry_plan, payroll_remit_plan},
     reports,
 };
@@ -955,14 +955,32 @@ impl Store {
     /// re-runs the deterministic close logic and checks the closing entry
     /// id against the journal.
     pub fn close_period(&mut self, id: PeriodId) -> Result<Option<EntryId>, StoreError> {
+        self.close_period_to(id, &CloseTo::RetainedEarnings)
+    }
+
+    /// Close a period with its net income going to `to`: Retained Earnings,
+    /// or members' capital accounts by share (see
+    /// [`ledger_core::Ledger::close_period_to`]). The target rides in the
+    /// journal so replay re-derives the identical closing entry.
+    pub fn close_period_to(
+        &mut self,
+        id: PeriodId,
+        to: &CloseTo,
+    ) -> Result<Option<EntryId>, StoreError> {
         // Pure pre-validation: a doomed close journals nothing, not even
         // the Retained Earnings account creation below.
         self.ledger.preview_close_period(id)?;
-        // Retained Earnings must exist before the close so its creation (if
-        // needed) is journaled as account.added; the close's own ensure
-        // then no-ops and replay stays deterministic.
-        self.ensure_control_account("3999", "Retained Earnings", AccountType::Equity)?;
-        let closing_entry = self.ledger.close_period(id)?;
+        if *to == CloseTo::RetainedEarnings {
+            // Retained Earnings must exist before the close so its creation
+            // (if needed) is journaled as account.added; the close's own
+            // ensure then no-ops and replay stays deterministic.
+            self.ensure_control_account(
+                ledger_core::RETAINED_EARNINGS_CODE,
+                "Retained Earnings",
+                AccountType::Equity,
+            )?;
+        }
+        let closing_entry = self.ledger.close_period_to(id, to)?;
         let entry_detail = match closing_entry {
             Some(eid) => {
                 let e = self
@@ -978,11 +996,21 @@ impl Store {
             }
             None => None,
         };
+        let close_to = match to {
+            CloseTo::RetainedEarnings => json!("retained_earnings"),
+            CloseTo::Members(members) => json!({
+                "members": members
+                    .iter()
+                    .map(|(account, share)| json!({"account": account, "share": share.to_string()}))
+                    .collect::<Vec<_>>(),
+            }),
+        };
         let line = self.append_journal(
             "period.closed",
             json!({
                 "id": id,
                 "closing_entry": closing_entry,
+                "close_to": close_to,
                 "entry": entry_detail,
             }),
         )?;
@@ -2738,15 +2766,44 @@ fn replay_line_into_ledger(
             let id = get_u64(p, "id")?;
             let want = p.get("closing_entry").and_then(|v| v.as_u64());
             // Deterministic: the close re-derives the closing entry from
-            // the replayed state, so it must match the journaled id. The
-            // journaled entry detail is for the projection; the ledger
-            // re-derives the entry itself.
-            let got = ledger.close_period(id)?;
+            // the replayed state and the journaled target (absent: Retained
+            // Earnings), so it must match the journal's id and every line.
+            let to = match p.get("close_to").and_then(|v| v.get("members")) {
+                None => ledger_core::CloseTo::RetainedEarnings,
+                Some(members) => ledger_core::CloseTo::Members(
+                    members
+                        .as_array()
+                        .ok_or_else(|| StoreError::JournalCorrupt("close_to.members".into()))?
+                        .iter()
+                        .map(|m| {
+                            let share = get_str(m, "share")?.parse().map_err(|_| {
+                                StoreError::JournalCorrupt("close_to member share".into())
+                            })?;
+                            Ok((get_u64(m, "account")?, share))
+                        })
+                        .collect::<Result<_, StoreError>>()?,
+                ),
+            };
+            let got = ledger.close_period_to(id, &to)?;
             if got != want {
                 return Err(StoreError::ReplayMismatch(format!(
                     "closing entry: journal says {want:?}, replay got {got:?}"
                 )));
             }
+            if let Some(eid) = got {
+                let replayed: Vec<Value> = ledger
+                    .get_entry(eid)
+                    .expect("close posted it")
+                    .lines()
+                    .iter()
+                    .map(journal_line_json)
+                    .collect();
+                if p["entry"]["lines"].as_array() != Some(&replayed) {
+                    return Err(StoreError::ReplayMismatch(format!(
+                        "closing entry {eid}: replayed lines differ from the journal"
+                    )));
+                }
+            }
         }
         "line.cleared" => {
             ledger.mark_cleared(

crates/ledger-store/tests/store.rs

@@ -457,3 +457,72 @@ fn receipt_corrections_are_journaled_and_survive_rebuild() {
     check(&store);
     store.verify().unwrap();
 }
+
+#[test]
+fn a_close_into_members_capital_replays_exactly() {
+    let dir = test_dir("members-close");
+    let mut store = Store::create(&dir, Currency::USD).unwrap();
+    let cash = store
+        .add_account("1000", "Cash", AccountType::Asset, None, false)
+        .unwrap();
+    let alice = store
+        .add_account("3000", "Capital — Alice", AccountType::Equity, None, false)
+        .unwrap();
+    let bob = store
+        .add_account("3001", "Capital — Bob", AccountType::Equity, None, false)
+        .unwrap();
+    let revenue = store
+        .add_account("4000", "Revenue", AccountType::Revenue, None, false)
+        .unwrap();
+    let jan15 = NaiveDate::from_ymd_opt(2026, 1, 15).unwrap();
+    let e = store.create_entry(jan15, "Sale").unwrap();
+    store
+        .add_line(
+            e,
+            cash,
+            Side::Debit,
+            Money::new(Decimal::new(10001, 2), Currency::USD),
+        )
+        .unwrap();
+    store
+        .add_line(
+            e,
+            revenue,
+            Side::Credit,
+            Money::new(Decimal::new(10001, 2), Currency::USD),
+        )
+        .unwrap();
+    store.post_entry(e).unwrap();
+    let jan = store
+        .create_period(
+            "2026-01",
+            NaiveDate::from_ymd_opt(2026, 1, 1).unwrap(),
+            NaiveDate::from_ymd_opt(2026, 1, 31).unwrap(),
+        )
+        .unwrap();
+    let half = Decimal::new(5, 1);
+    store
+        .close_period_to(
+            jan,
+            &ledger_core::CloseTo::Members(vec![(alice, half), (bob, half)]),
+        )
+        .unwrap();
+    // 100.01 splits 50.01 / 50.00 into the capital accounts.
+    let balances = |s: &Store| {
+        (
+            s.ledger().account_balance(alice).unwrap(),
+            s.ledger().account_balance(bob).unwrap(),
+        )
+    };
+    let want = (Decimal::new(5001, 2), Decimal::new(5000, 2));
+    assert_eq!(balances(&store), want);
+    let journal = std::fs::read_to_string(dir.join("journal.jsonl")).unwrap();
+    assert!(journal.contains("\"close_to\":{\"members\""));
+
+    drop(store);
+    let mut store = Store::open(&dir).unwrap();
+    assert_eq!(balances(&store), want);
+    store.rebuild().unwrap();
+    assert_eq!(balances(&store), want);
+    store.verify().unwrap();
+}

docs/mcp-interface.md

@@ -279,10 +279,13 @@ R-FUTURE-3 and rides the engine roadmap, not the MCP layer.
 - `books.create_period { name, start, end }` → `{ period_id }`.
   Dates are YYYY-MM-DD, inclusive.
 - `books.close_period { period_id, confirmed? }` → without confirmation:
-  `{ status: "preview", lines: [...] }` showing the closing lines and posts
-  nothing; with `confirmed: true`: posts the closing entry (revenue debited
-  to zero, expenses credited to zero, net to `3999` Retained Earnings) and
-  marks the period closed. Closed periods reject new entries.
+  `{ status: "preview", lines: [...] }`: the exact closing entry (the close
+  run on a copy of the ledger), posting nothing; with `confirmed: true`:
+  posts it and marks the period closed. The entry zeroes revenue and
+  expense balances as of the period end; the net goes to `3999` Retained
+  Earnings, or, with `[[company.members]]` in `wanderbooks.toml`, to each
+  member's capital account by share. Periods close in order. Closed periods
+  reject new entries.
 - `books.list_periods {}` → `{ periods: [{ id, name, start, end, status,
   closing_entry }] }`.
 

docs/requirements.md

@@ -111,8 +111,16 @@ requirement conflict, the requirement wins.
   Reports work in base currency. (Full per-account currencies and translation
   remain future.)
 - **R-? — Periods and close.** Was R-FUTURE-2.
-  `ledger-core::periods`: `create_period`, `close_period` (posts closing
-  entry to `3999` Retained Earnings), closed periods reject new entries.
+  `ledger-core::periods`: `create_period`, `close_period_to(id, to)`; closed
+  periods reject new entries. The closing entry, dated at period end,
+  zeroes each revenue and expense account's balance **as of the period
+  end** (later-dated entries belong to later periods) and puts the net in
+  `to`: `CloseTo::RetainedEarnings` (`3999`, the corporate convention;
+  `close_period` is shorthand) or `CloseTo::Members` (each member's capital
+  account by share, to the cent, the last absorbing rounding: the
+  partnership convention). Periods close in order (`CloseOutOfOrder`). The
+  journal records the target, and replay re-derives the closing entry and
+  checks every line against the journal.
 - **R-? — A/R and A/P workflows.** Was R-FUTURE-5.
   `ledger-core::arap`: customers, vendors, invoices, bills, payments,
   AR/AP aging. MCP tools for the full workflow.

plan/STATUS.md

@@ -204,4 +204,14 @@ interface is MCP, not a cloned GUI. The first storage + MCP slice is done
   (loss), standard cash-flow wording) and an "Accrual basis · Prepared …"
   footer. "Today" is local time, not UTC (evening exports were dated
   tomorrow).
+- 2026-10-11: Period close fixed and made partnership-aware. The close swept
+  every revenue/expense posting ever made, so a period closed after later
+  entries existed swallowed them (closing January in March closed February
+  and March too); it now zeroes balances as of the period end, refuses to
+  close out of order, and its preview is the real close run on a copy of
+  the ledger. A multi-member LLC closes into each member's capital account
+  by share (CloseTo::Members), the partnership convention, so capital
+  accounts carry allocated earnings; the members'-equity statement treats
+  those closes as income, not contributions, and the balance sheet shows
+  only unallocated earnings. Replay now checks closing lines, not just ids.