In theory as a government employee you already fear getting in trouble with OGE (Office of Government Ethics) and in normal times this is truly enough. Nobody wants to have a conflict of interest or fail to disclose investments etc. However nothing is normal under the current administration...

Every large company should ban employees and contractors from trading on prediction markets. There are so many ways an employee could make money on prediction markets. Causing outages is probably the easiest, but anything that would get the company in the news would do it.

The US federal workforce is ~2.2 million people. Banning them all from trading on prediction markets isn't the right move. A cafeteria worker in some suburban admin office likely has no inside information they are going to trade on. Members of congress and other high level positions on the other hand should be banned.