Am I overlooking something, or would that mean it’s super easy for a rational participant to make money?

Sometimes. Often the sure fire bets have lower returns than the expected annual stock market returns.

You have to watch out for resolutions are don’t depend on the truth or could be abused.

Examples of markets to avoid are those that a single individual can manipulate. They could take the most profitable side and corrupt the result.

gpm 4 hours ago | parent | prev [-]

Presumably it's a negative expected value game - the company running it has to make money after all... so likely not.

Prediction markets don’t need a bookie. Each bet has another real person taking the other side.

It’s more like the stock market brokerages. They just take a fee on each trade and don’t need to give you a spread over the stock price

	▲	gpm 3 hours ago \| parent [-]
		This subthread is not about prediction markets