No one is going to steal it. Not if it’s actually a big idea.
One thing that big ideas have in common is that they’re almost impossible to give away.
You could have bought Amazon stock for lunch money, been an early backer of Acumen, financed part of Spike Lee’s first movie, had front row seats to Hamilton, bought BTC for $2… you get the idea. Even insiders usually take cash instead of stock options. And early customers almost never race out to build a competitor.
When big ideas show up, almost no one sees what’s possible. All they notice is that change is risky and new stuff might not work.
Don’t worry so much about someone stealing your ideas. In fact, it’s probably worth working harder to get people imagining that they might.