Sweep

Summary

A sweep, in the general treasury sense (see Wikipedia: Sweep account), is a process that automatically moves or converts balances from many accounts into one central place on a regular cadence, concentrating liquidity that would otherwise sit idle and scattered. ORE Studio's domain model uses the same word for a family of processes sharing that shape – go through every book, or an eligible subset of them, and centralise or convert something – but the two concrete sweep types built on it, Spot Sweep and Ledger Sweep, turn out to be operationally quite different processes that happen to share this name and a cash-centralisation goal. They sit at different layers (front/middle office versus accounting/ledger), run on different cadences (periodic and discretionary versus daily and automatic), apply to different populations of books (only Is Sweepable books versus every ledger book unconditionally), and produce different kinds of P&L (realised versus unrealised).

Detail

The general shape: a process, not a single mechanism

What every sweep shares is a structure, not a specific implementation: some process runs across a population of books, examines a balance or position on each, and either moves it somewhere central or converts it into another currency, on some cadence. This shape is exactly what sweep accounts describe in ordinary banking – automatically moving surplus funds from many operational accounts into one investment or treasury account – and ORE Studio's own sweeps follow the same pattern at the level of trading books rather than bank accounts. Recognising this shared shape is useful precisely because it explains why two otherwise unrelated processes both earned the name "sweep": each is, in its own layer, a sweep account by another name.

Why "sweep" names two different processes

Spot Sweep is a front/middle-office process that periodically crystallises profit held in non-presentation currencies by aggregating and converting Is Sweepable-flagged books' cash balances into a designated Central Sweep Book.
Ledger Sweep (FX Revaluation) is a daily, automated, accounting-layer process that revalues every ledger book's transactional-currency balances into its functional currency – it is not opt-in, and is unrelated to the Is Sweepable flag.

The two are easy to conflate because they share a name and the same underlying goal of cleaning up cross-currency exposure, but they differ on every operational axis that matters:

Aspect	Spot Sweep	Ledger Sweep
Layer	Front/middle office, trading	Accounting/ledger
Cadence	Periodic, discretionary	Daily, automated
Scope	Only `Is Sweepable` books	Every ledger book, unconditionally
P&L	Realised (real executed trade)	Unrealised (valuation only)
Output	Executed FX sweep trade	FX Revaluation P&L entry only

Sweep target and remittance target are not combinable

The book that Spot Sweep centralises balances into (the Central Sweep Book) and the book that Central Remittance accumulates profit into (the Central Remittance Book) look superficially similar — both are singleton "central" books that other books' balances flow into — but they are not the same role and should not be modelled as combinable flags on one book:

Different owners: Spot Sweep is a Treasury/Money-Markets desk process, run frequently; Central Remittance is a Finance/Group Treasury process, run monthly to annually.
Different accounting treatment: Spot Sweep crystallises real trading P&L (the average-rate mechanism generates an actual FX gain/loss); Central Remittance is deliberately balance-sheet-only — it must not touch P&L a second time, since it only relocates already-recognised profit.
Different population: Sweep-target balances come from many trading books' live spot/cash positions; remittance-target balances come from the global books that already received the monthly Profit Sell Down mirror deal — a step removed and already Finance-owned.

Mixing live trading P&L postings (Sweep) with P&L-neutral relocation postings (Remittance) on the same book balance would undermine exactly the audit/reconciliation separation these processes exist to provide — the same reasoning that keeps Reserve and Funding book purposes apart (see Book classification). Sweep target and remittance target are therefore modelled as two further mutually-exclusive values of book_purpose_type, not as independent boolean flags a book could carry simultaneously.