Simulate selling prediction-market shares before resolution

Start With the Net Number

A resale simulation answers one narrow question: if you buy a quantity of shares at one executable price and sell them at another before the market resolves, what net cash difference does that leave under your cost assumption? The implemented tool computes fixed quantity times (exit price minus entry price), minus total assumed costs. Prices must sit between 0 and 1, quantity must be positive, and costs cannot be negative. That matters because the price you see on a prediction market is often the midpoint of the best bid and best ask, or a stale last trade when the spread is wide, and it is not a promise you can buy or sell there.

Run the 2 worked cases that come with the tool. Case 1: 100 shares, exit-entry difference of 0.15, assumed costs 2, so 100 times 0.15 equals 15, then minus 2 equals 13. Case 2: 100 shares bought at entry 0.40 and sold at an assumed exit 0.30, so 100 times (0.30 minus 0.40) equals minus 10, then minus 10 minus 2 equals minus 12. Those are the 2 worked cases. Any additional examples on this page are illustrative and built from the same formula. No live quote, cashback, forecast, held resolution payout or liquidity guarantee is included.

The main limitation is baked into the inputs. The tool assumes the full quantity fills at a single price and that costs are one fixed number. Real market orders can consume several price levels and incur slippage, so your average fill can be worse than the exit price you typed. If that gap drives your decision, check whether the book supports your size using the guide on order-book depth and executable quotes.

What Each Input Means

Shares is the number of contracts you hold or plan to hold. Entry price is the executable price at which you acquired them, not the midpoint you saw on a chart. Exit price is the executable price you expect to receive when you sell, also between 0 and 1. Total assumed costs is everything you treat as a deduction, such as fees or a slippage buffer, in the same units as a share payout. Mix currencies, or forget that one leg can be cheaper than the other, and the tool still returns a number, but that number describes a different decision.

Selling before resolution and holding to resolution answer different questions. This tool uses the resale price you enter and your assumed costs. Use the settlement calculator when you want to compare the outcomes of holding until resolution.

A boundary case: buy at 0.60, sell at an assumed 0.60, zero costs, and the tool returns exactly 0. That is break-even before costs, not a profit. Add any positive cost and the same round trip turns negative.

Run the Formula by Hand

Gather 4 numbers: shares, entry price, exit price, total assumed costs. Multiply shares by the exit minus entry difference, then subtract costs. For 50 shares, entry 0.20, exit 0.35, costs 1.5: 50 times 0.15 equals 7.5, then minus 1.5 equals 6. For the same 50 shares, entry 0.50, exit 0.35, costs 1.5: 50 times minus 0.15 equals minus 7.5, then minus 1.5 equals minus 9. The second case catches the common trap of reading only the exit price. When exit is below entry the signed difference is already negative, and costs push it further down.

The formula is linear in every input, so a small exit change shifts the result by shares times that change. With 100 shares, a 0.01 lower exit moves the result by minus 1 before any cost adjustment. That is why an assumed exit of 0.30 rather than 0.31 is not cosmetic on a 100-share position.

An explicit limit: the tool does not model partial fills, queue position, time to fill, or a book that moves while you wait. If your order is large relative to available depth, the assumed exit may be optimistic. Treat the output as a scenario, not an executable promise.

How This Differs From Neighbouring Tools

The resale simulator answers whether an assumed sale price and assumed costs leave you above or below your entry. A settlement calculator addresses holding until resolution. Our guide to maker and taker rules can help you examine documented fee parameters. Choose the tool that matches the decision you are examining.

When the resale number lands near zero, the next question is usually whether the book can absorb your size. That is a depth question, not arithmetic.

A Concrete Comparison of Exit Scenarios

The table below keeps 100 shares, entry 0.40 and assumed costs 2 fixed, and moves the exit price from 0.30 to 0.50. Every value is an illustrative input, not a market forecast. The only sourced fact behind the rows is the implemented formula, quantity times (exit minus entry) minus costs, with prices constrained to 0 through 1.

The row at exit 0.30 reproduces the worked case: 100 times (0.30 minus 0.40) equals minus 10, then minus 2 equals minus 12. The row at 0.40 is 0 before costs and minus 2 after. The row at 0.50 is plus 8 after costs. The after-cost break-even sits above the entry price because the 2 of costs must be recovered first: with 100 shares, that is an exit of 0.42 for zero net profit, and above 0.42 for a positive result. Change the cost assumption and the threshold moves. At 0 costs it is exactly 0.40, at costs 5 it is 0.45. The tool shows the consequence of the cost you enter; it does not choose it for you.

What the Simulator Does Not Know

It does not fetch a live quote, so the exit price is yours to supply. It does not account for cashback or maker rebates that change effective cost. It does not simulate the held resolution payout, does not estimate event probability, and does not guarantee that depth exists to fill your quantity at the assumed price. It also does not cover the case where the market resolves before your sell order fills.

Because liquidity is ignored, a positive net result is not proof you can capture it. With a wide spread or thin depth the average fill can be worse than the exit you typed, and the displayed price may have been only a midpoint or a stale last trade. That is a limit of the input, not a flaw in the arithmetic: the arithmetic is exact for the assumptions given.

Your Next Decision

If the simulated net result is negative at a realistic exit, holding to resolution is a different path and belongs in the settlement calculator, not here. If the result is positive but thin relative to your size, the next check is whether the book can absorb the quantity, which the liquidity guide covers. If your costs are still guesses, replace them with a sourced estimate before trusting the output.

A practical, explicitly illustrative protocol: pick 3 exit prices (pessimistic, expected, optimistic), run the formula for each with the same shares and costs, and write down the range. If even the optimistic case is negative, resale is unattractive under those assumptions. If the pessimistic case stays positive, the arithmetic absorbs some slippage. Either way you get a signed number, not a recommendation.