A final-round day is commonly four or five back-to-back interviews, often with a trading game and sometimes a meal. Candidates prepare for the questions and not for the day, which is a mistake, because the questions are usually not what separates people by the afternoon.
Stamina is a real variable
Performance in round one and round five is rarely comparable. Interviewers know this and account for it partially, but not fully.
What helps: eat properly beforehand, take water when offered, and use the two minutes between rounds to reset rather than to replay the last one. Ruminating on a question you fumbled is the most expensive thing you can do with that time.
Each round is mostly independent
Interviewers typically go in without a detailed briefing on how you have done so far - partly by design, to avoid anchoring. A bad round is survivable and is not usually visible to the next person.
Behave accordingly. Walking into round three visibly deflated turns one bad round into three.
But feedback carries
The exception, and it matters: if an interviewer corrects something, that correction may well be re-tested later in the day, and at least one firm names applying earlier feedback as an explicit criterion. Treat every correction as a live instruction rather than a closed conversation.
The trading game
Common in trading pipelines. You will quote a market, someone will trade against you, and you will be expected to know your position afterwards. See how to make a market and practise with the market-making game.
The most common failure is not mispricing - it is losing track of inventory after a few trades.
The lunch is an interview
Friendly, and assessed. The question being answered is whether people want to sit next to you for ten hours a day. That is a real hiring criterion at firms that work in close physical proximity, and it is not a trick.
Do not relax into indiscretion, and do not perform. Be a normal person who is interested in the work.
Your own questions
You will be asked several times. Have more than two prepared, and vary them by who you are talking to - a desk trader and a recruiter can answer different things well.