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Learn · Sources checked Sep 27, 2026

You had a big win. Now the boring part.

A big win is a money problem before it is a trading problem. There is a bill nobody mentioned, a balance that stops feeling like money, a position size that grows without anyone deciding to grow it, and a bankroll that quietly turns into your savings. This section is about the week after: what to set aside, what to move, how big the next bankroll should be, and why won money gets risked faster than earned money does. It is education, not tax or financial advice, and it makes no claim about anyone’s results. The week after looks much the same whatever the number was.

The four moves

  1. Work out what you owe, and put that money somewhere you will not trade with. The bill is the part nobody plans for, and it is the one with a deadline attached.
  2. Move the rest off the exchange the same day. A balance you can see is a balance you can size against. Cash in a bank account is not.
  3. Decide the next bankroll as a number, before you place anything. Write the figure down while the account is closed. That is the whole of it.
  4. Leave the protected money alone long enough to be boring. Money whose job is to sit still only does that job if nothing keeps asking it to work.

In that order, and the first one first. Everything else in this section is one of these four in more detail.

Why this section exists

Stake size goes up after a win. This is the best-evidenced thing on the page. Four independent sets of real betting records say the same thing. In 1,913,251 bets from 2,000 online casino players, the next bet after a win rose by roughly 3.4% per standard deviation of win size on slots and 13.5% to 16.7% on blackjack and roulette Sci Rep 2024. In 565,915 online sports bets, the mean stake after a win was £18.47 against £10.89 after a loss Cognition 2014. Among 36,328 real sports bettors, a big win was followed by more engagement, more losses and more risk in the following weeks, with the effect fading over time Comput Hum Behav 2023. Watched directly at a roulette table, players placed more bets and covered more numbers after winning than after losing J Risk Uncertain 2005.

The reason usually given for it is shakier than the effect itself. The house money effect, the finding that a prior gain makes people accept gambles they would otherwise refuse, is a real laboratory result Manage Sci 1990. A 2023 replication with 241 participants across four endowment conditions found that windfall money did raise risk tolerance, but that the classic house money effect did not appear in three of the four treatments J Risk Uncertain 2023. So: the behaviour is well measured in real money, and the tidy explanation for it is not settled. We are not going to pretend otherwise.

One thing you may have read is not true. The claim that some large majority of big winners end up broke is folklore, and the organisation it is usually credited to has publicly disclaimed it. The best-identified study of the question followed 34,987 Florida lottery winners and found large winners were about half as likely to file for bankruptcy in the first two years, and equally more likely in years three to five, with no net difference across five years Rev Econ Stat 2011. Sudden money postponed financial trouble rather than causing it or fixing it. That is a more useful finding than the statistic ever was, and it is the reason this section is about the first week rather than about your character.

None of this tells you to stop. It says that the size of the next position is a decision, and that after a win it gets made by default unless you make it on purpose. The reset monitor on the desk pages is the same idea in five minutes, and bankroll and units is the sizing rule this section hands the money back to.

Everything in this section

Thirteen pages, built in waves. A title without a link is not written yet, and it is listed anyway so you can see the shape of what is coming rather than finding out by clicking.

The bill

  • Tax on prediction-market profits

    What is owed on a Kalshi profit, which of three readings applies, and the part the IRS has not answered.

    Not written yet

  • Set aside the tax money

    Hold back a share the day the money lands, before it has a job and before the next trade.

    Not written yet

  • Gambling winnings or contract profits

    Three competing treatments of an event contract, and why the answer changes the bill.

    Not written yet

The move

  • Move it the same day

    Why the withdrawal happens today rather than after one more trade.

  • Emergency fund first

    A bankroll and an emergency fund are the same money until you separate them.

    Not written yet

  • The new bankroll

    Keep playing, deliberately, small. How to set the next size as a number before you place anything.

The money that sits still

Your head

  • House money

    Won money gets risked faster. What the research shows, and the part of it that does not replicate.

  • Size creep

    The position that grew without anyone deciding to grow it.

    Not written yet

  • When a win is a warning

    The signs that a good run is turning into something else, and what to do about them.

Reading your own run

  • Streak or skill

    How many graded results it takes before a run means anything at all.

    Not written yet

  • What the run cost

    The fees a winning week actually paid, from the published formula.

    Not written yet

What this section is not

  • Not a tax calculator. A number computed from your filing status and your state is a determination about your situation, it would be wrong for somebody, and it is not ours to make. A worked example with every assumption printed, next to a link to the IRS page it came from, is as far as we go IRS Pub 525.
  • Not a recommendation of any account, fund or provider. No best-of list, no comparison table, no rates. We are a prediction-market site and we are not the right people to take that from.
  • Not a number for how much you should keep playing with. A tool that answers that question has told you what to risk, whatever the disclaimer under it says.
  • Not a story about somebody who turned a small stake into a large one. The site has never published a figure like that and it is not starting here.

Start with these three lessons

Questions people ask

How much of a big win should I set aside for tax?

There is no share that is right for everyone: it depends on filing status, the state you live in and your other income for the year, and we are not the right people to compute it. What anyone can do is pick the fraction before the money has a job, move it out of the trading account the same day, and take the actual figure to a tax professional or to the IRS’s own pages.

Does taking a break after a big win stop me giving it back?

It reliably stops the session you are in. A one-month randomised trial of 12,510 online gamblers found that longer mandatory breaks lengthened the gap before the next session, and that the effect largely faded once the trial ended. The defensible claim is about today, not about changing how you trade next month.

Is it true that most big winners end up broke?

The figure usually quoted is folklore, and the body it is attributed to disclaims it. The best-identified study, of 34,987 Florida lottery winners, found large winners were about half as likely to file for bankruptcy in years one and two, and equally more likely in years three to five, with no net difference over five years. Sudden money postponed trouble rather than causing or curing it.

Should I stop trading after a big win?

That is your call and this section does not make it for you. What the betting records show is that stake size and exposure rise after a win, across four independent real-money datasets. So if you keep going, the size is the thing to settle on paper first, while the account is closed.

This is education, not betting, tax or financial advice, and nothing here is a claim about anyone’s results. Only risk what you can afford to lose, and set a money limit before you start. Gambling problem? Call or text 1-800-MY-RESET, or chat at 1800myreset.org. Kalshi users can set funding caps and opt-outs in the Responsible Trading Hub.