The Time Decay Nobody Talks About: Why Holding Winners Too Long Kills Your Returns

The Trade You Forgot to Close

You bought Trump at 42¢ in March. It's September and he's sitting at 88¢. Feels great. You're up big on paper and you keep telling yourself you're 'riding the winner.'

Here's the uncomfortable question: would you buy that position today at 88¢?

Because every day you don't sell, that's exactly what you're doing. You're rebuying it.

Prediction Markets Have Their Own Theta

Options traders obsess over time decay. Prediction market traders mostly ignore it, which is weird because the math is even simpler.

When you hold a YES contract at 88¢ that resolves in 60 days, you've locked up capital that could earn a 12¢ return over 60 days — assuming you're right. Annualize that and you get roughly 90% APR on a position with real tail risk.

Sounds amazing until you flip it: you're taking on 12% downside for a 13.6% upside, over two months, with your capital frozen. If your model says the true probability is 92%, you have edge. If your model says 88%, you're literally holding a position with zero expected value while assuming binary risk.

The higher a contract climbs, the worse the risk/reward gets. This is obvious. Nobody acts on it.

The Endowment Effect Wearing a Trader's Hat

Why do we hold? Because selling a winner at 88¢ feels like leaving money on the table if it resolves at $1.00. And the human brain weights that missed 12¢ heavier than the 88¢ you'd get to redeploy immediately.

But redeploying is the entire game. Capital that's locked in a 92%-to-resolve position is capital that isn't hunting the next 40¢ mispricing. Your bankroll's job is to compound, not to babysit contracts through their victory lap.

A Framework: The Rebuy Test

Before holding any position, ask: at the current price, with the current time to resolution, would I open this trade fresh?

If no, you don't have a winner. You have a losing trade you happen to be up on.

The cleaner version, if you like numbers:

- Estimate true probability: p

- Current price: c

- Days to resolution: t

Your annualized expected return is roughly ((p − c) / c) × (365 / t).

A position at 88¢ that you think is 92% to hit, 60 days out: ((0.92 − 0.88) / 0.88) × (365 / 60) ≈ 27.7% APR.

Not bad — but is it better than what you could do with that capital elsewhere on the platform right now? That's the real benchmark. Not zero. Not T-bills. Your next best trade.

When Holding Actually Makes Sense

A few cases where riding it out is correct:

- You have no better opportunities. Sitting in a 92%-likely 88¢ contract beats sitting in cash if the alternative is boredom-betting on a market you haven't researched.

- Exit friction is real. Thin books, wide spreads, or fees that eat your remaining edge. Sometimes you're stuck and that's fine.

- Your edge is growing, not shrinking. New info made you *more* confident since you entered. Rare, but it happens.

The Habit to Build

Once a week, look at every open position and mentally close it. Then decide if you'd reopen at current prices. The ones that fail the test get sold — not because they're going to lose, but because your capital has a better job to do.

Good traders don't fall in love with winners. They fall in love with turnover.