This paper explains how the modeled results were produced and what they represent. Sampo's rule is proprietary, and parts of it are patent pending; this paper describes the data and the measurement, not the rule.
The data is synthetic
Every number in these materials comes from a synthetic simulation. There is no production bank data and no Fedwire transaction data, and the 125 "days" are synthetic weekday labels, not an observation period. We built a synthetic book to demonstrate the mechanism, run sensitivities, and design a bank-data pilot without using any bank's confidential data. Real results will differ; a pilot on a bank's own payments confirms the opportunity.
How the synthetic book is built
The generator is referenced to published Fedwire structure along three axes:
- Who pays whom. A money-center core of five banks with a fixed directed graph of payment relationships, so the network structure stays stable across the history while the flows are redrawn each day.
- How large payments are. Large-value payment sizes are extreme right-skewed. We fit a lognormal to the admitted tail using published exceedance shares above $100m, $1bn and $2bn, then draw each in-scope payment from that distribution truncated to the configured $500m–$5.1bn range.
- When they arrive. A peak at the opening and a larger one in the late afternoon, matching the published intraday shape of a system with no coordination.
For each day, the generator draws new amounts, the times the banks send the payment intents, and each payment's own time, from a documented, deterministic seed sequence. The result is a 125-day book of 62,500 payments (500 a day across five banks), with values from ~$500m to $5.1bn (median ~$972m, mean ~$1.08bn). The full parameters, sources and regeneration procedure are documented in the internal data-generation methodology.
How the saving is measured
For each day we compare the same payments without Sampo and with Sampo:
- Without Sampo. Every payment is submitted at its own time. We measure each bank's modeled in-scope peak net debit: its largest net debit at the end of any minute in the day, and zero if it never goes into net debit (technical name LNNCP).
- With Sampo. Sampo advises banks to submit some payments early, never later than their own time. Its no-worse-off guard aims to reduce the risk that a bank is worse off. It is not a guarantee.
A bank is worse off on a day when its realised peak net debit with Sampo is above its peak without Sampo.
The headline ~49% reduction in modeled in-scope peak net debit is in the cohort monthly peak net debit: the sum of each bank's monthly peak, found separately, averaged over the complete calendar months February and March of the synthetic history. It falls by 49.3% (~$55.4bn). On an average-day basis the reduction is 59.0%. Balances are sampled on the Fedwire convention: net all settlements in an operating minute, then sample at minute end. An intraminute convention, sampling after each settlement, is available for other rails.
What the model leaves out
The metric is modeled in-scope peak net debit, not a bank's total intraday liquidity requirement. The model omits opening account balances, below-threshold and other out-of-scope flows, other rails, collateral and credit facilities, real RTGS queue, rejection and finality behavior, cancellations and repairs, and submission-to-settlement latency (the prototype uses one timestamp for both). It is suitable for demonstrating the mechanism and designing a pilot, not for estimating a Fedwire tail, actual daylight credit, bank P&L, regulatory capital or a required liquidity or HQLA buffer.
The bank owns the economic translation
Any monetary value is a sensitivity the bank supplies, not a product claim:
annual value = reduction in modeled in-scope peak × recognition factor × cost of liquidity
The recognition factor (0–100%) is the share the bank's approved methodology recognizes. The cost of liquidity is an annual rate that the bank supplies: what holding one unit of liquidity for a year costs it. The annual value is computed for each bank, at its own factor and rate, and summed over the banks. At 100% recognition and a cost of liquidity of 1% a year, the monthly default implies an illustrative ~$554m annual value. This is not a funding-cost fact, a Fedwire fee, or booked P&L.
The current synthetic dataset
The current dashboard is a deterministic synthetic test of the mechanism.
| Property | Current dataset |
|---|---|
| Banks | 5 pseudonymous banks |
| Synthetic history | 125 date labels |
| Payments | 62,500; exactly 500 each day |
| Payment values | ~$500m–$5.1bn; ~$972m median and ~$1.08bn mean |
| Mean selected value | ~$539bn per day; 11.74% of 2025 Fedwire daily value |
| Opening batch | 29.85% of payment intents sent at the opening |
| Comparison | Without Sampo: every payment submitted at its own time, which is unique for each payment |
The bank roster, complete directed pair graph and number of payments on
each pair stay fixed across the history. The generator redraws amounts, the times the
banks send payment intents, and own times for each day, using the documented,
deterministic seed sequence. Each payment's own time (latest_ms) equals its synthetic
settlement time (historical_settlement_ms). Sampo may advise a payment earlier than
its own time, never later.