On Sunday the U.S. struck Iran again, triggering swift losses on Polymarket positions previously seen as nearly risk-free. The episode highlights structural risks in prediction markets when contracts resemble short-term bonds with heavy downside asymmetry.

How bond-like contracts form on prediction markets

Some prediction contracts trade close to 99 cents with limited time until settlement, which makes them look like short-duration bonds for traders seeking tiny but steady returns. Buyers who pay high entry prices expose themselves to total loss if the outcome flips, despite frequent small wins beforehand.

Loss asymmetry and recent cases

The payout profile is asymmetric: a buyer risks nearly their entire stake to win a marginal amount, and a single adverse event can wipe out accumulative gains. Market participants who consistently choose contracts priced near certainty face concentrated tail risk.

• MEPP publicly lost about $40 K on such positions.
• meagainsttheworld converted $23.4 K into $273 K by taking the opposite side in similar trades.
• Earlier in the year, similar swings included approximately $6.5 M in a single day in February and about $650 K affecting Cinibengales in March.

Who benefits and who loses

Patterns show that traders entering positions hours before events commonly end up on the winning side, while those holding long odds through breaking developments bear disproportionate losses. The structure therefore creates recurring opportunities for counterparties willing to take high-risk, event-driven positions.

Implications for participants

Participants should treat contracts trading near certainty as instruments with significant tail risk rather than as safe short-term yield; risk management and position sizing become decisive in such environments.