Around this time every year, we conduct NerdWallet’s annual broker review process. We assess what’s changed in the industry, discuss which brokerage features matter most (and which ones now matter less), and finally, we do the work by opening accounts to test them.

Prediction markets, which have made their way into some of the most popular investing apps, came up more than we expected in testing this year.

At first, we decided to simply collect information on who does and doesn’t offer access to them, without intending to reward or penalize a broker either way.…