A Bank Holiday Isn't Inefficiency, It's a Fraud Control
When the financial system goes dark on weekends and holidays, it looks like technological backwardness. It's actually a deliberate control: it keeps conspirators from all sitting at the keyboard at the same time, and that exposes internal fraud.
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The argument · timestamps estimated from transcript position
A holiday is a Schelling point both sides default to
A holiday isn't an authoritative list; it's a Schelling point you and your counterparty default to on your own. Nobody questions that Christmas is a holiday in the US, so nobody has to ask. But a holiday can also be the product of explicit negotiation: one reason government payroll modernization projects keep failing is that it takes a historian doing a lot of bespoke research to determine which document governs the overtime rate for a Chicago parking enforcement officer on Good Friday. A holiday is both a fact ‘every child knows’ and a negotiable object you can litigate.
— Patrick McKenzieThe Bank of Japan's Company Foundation Day is on no official list
The Bank of Japan is also a Japanese company, so some of its human and computer systems rest on days when most office workers are at work, because that day is the bank's own Company Foundation Day. Institutions that interact with it inherit the counterparty's company founding anniversary for certain operations. This holiday appears on no list in government publications, Bloomberg, or Google Calendar, yet it carries all the consequences of a holiday. Once you trip over it, the engineering team has to urgently redefine how the system understands global holidays — because when the system asks ‘is today a holiday’, it usually passes in a jurisdiction but not a counterparty.
— Patrick McKenzieBlack Friday falls inside the four days when money doesn't move
Black Friday is the day after Thanksgiving, Cyber Monday follows right behind, and transaction volume on those two days spikes as predictably as the sun rising — and they land squarely inside a four-day window in which the banking system basically doesn't move money between companies. If you promise a customer ‘we'll send the payment the next business day’ while the underlying rails take two business days to get the money to you, you have a one-day mismatch, and that mismatch consumes float. Normally you only have to front one day, three days over a weekend, and around five days during BFCM, which includes the biggest sales day of the year. So hundreds of people spend weeks ahead of time walking through BFCM scenarios, writing contingency plans, and modeling float requirements with finance.
— Patrick McKenzieCrypto tried 24/7, and two banks closing at once broke it
Heavily online technologists hate systems that go down on a predictable schedule, and the crypto crowd especially loves distributed systems that are always on with no single point of failure. One idea is to have every market participant bank at the same bank, get internal APIs for book transfers, and money can flow 24/7, with a second bank for redundancy. Crypto did try this path, and then in 2023 discovered just how questionable the design was when two highly correlated banks closed on adjacent weekends at the same time. The lesson: systems that mediate between cultures are useful, and mediating systems often need to bridge gaps in operating schedules — a gap you can't eliminate by declaring ‘the only operating schedule is 24/7’.
— Patrick McKenzieForced vacation is meant to keep conspirators from assembling
Banks deliberately create misaligned operating schedules; it's an important tool for detecting and containing certain kinds of fraud. The most terrifying fraud comes from insiders who know the back-office processes: a single insider who understands the back office is enough to bring down a bank or cause billions in losses — Barings and Daiwa in '95, Société Générale in '08, UBS in '11 are all examples. One very old control is forced vacation, whose purpose is to keep the group involved in a conspiracy from assembling enough co-conspirators, in the right place on the right day, all sitting at the keyboard at the same time. So a finance CEO sleeping on a beanbag chair in the office may be very dedicated, but both the company and he himself had better not allow it.
— Patrick McKenzieExpecting the financial system to be always on isn't even self-consistent
In a world that's increasingly interconnected, where decision-makers care more and more about nines, it's reasonable to expect the financial system to partly narrow the gap between historical practice and contemporary practice. Culture creates systems, and systems create culture; both change, and infrastructure changes far more slowly than fashion, but it does change. Still, expecting the financial system to run continuously isn't just something you shouldn't expect — it isn't even a self-consistent expectation: the financial system is an interconnected network of organizations, systems, and subsystems nested layer upon layer, resting at the bottom on individuals who have been made complex sociocultural promises and who have a physiological need for sleep. These people will keep resting and celebrating periodically, just as they keep working for the society the financial system supports.
— Patrick McKenzieIn their own words · checked verbatim
A holiday is any day you and your counterparty mutually agree is a holiday.
Patrick McKenzie3:29
Guess which holiday none of the above data sources will mention. But it is definitely a holiday , because it has all the consequences of being a holiday .
Patrick McKenzie6:00
You need to float five-ish days, including the largest sale day of the year . And you whisper fervent prayers that all the wires you expect arrive exactly when you expect them.
Patrick McKenzie10:33
systems which intermediate between cultures are useful . Intermediating between cultures is a thing the world urgently needs and is extremely prepared to pay for . Systems which intermediate between cultures will frequently need to cross a gap between operating schedules. You cannot simply wish away that gap.
Patrick McKenzie21:29
A very old control for this sort of thing is forcing holidays, with the goal that the set of staff engaged in a conspiracy don't have a sufficient number of conspirators at the keyboard, in all the right places, on all the right days, the conspiracy needs to operate to be undetected.
Patrick McKenzie23:30
If we didn't have holidays, we'd have been forced to invent them. We accept degraded performance (very useful humans: not at keyboard!) as an organizational chaos monkey to shake out far more serious issues.
Patrick McKenzie25:00
But should one expect the financial system to operate constantly? Not only should you not expect that, that is not even a coherent thing to expect.
Patrick McKenzie26:31
Figures
| Stripe's 2025 Black Friday Cyber Monday processing volume | about $40 billion | 18:27 |
| Financial system availability level | closer to five twos than Google's five nines | 1:31 |
| Days of float that must be fronted during BFCM | about five days | 18:27 |
Glossary
- float
- Money you legally hold temporarily because of business dealings; positive float means you're using someone else's money, negative float means they're using yours.
- Schelling point
- A default coordination point both sides can settle on without communicating; holidays often rest on one.
- five nines
- 99.999% availability, roughly five minutes of downtime per year.
- chaos monkey
- A mechanism that deliberately injects random failures to expose system weaknesses.
How to listen
Engineers and product managers working on payments, clearing and settlement, and cross-border financial infrastructure, plus finance practitioners who care about operational risk and internal control design.
The sponsor read from 15:07 to 18:27 can be skipped.