For years, BrewDog invited fans to become “Equity Punks.” Not just customers. Owners. Across seven crowdfunding rounds, roughly 220,000 investors poured in about £75 million (that’s more than $100 million).

Now, as BrewDog explores a sale or break-up, many Punks may be staring at a zero return, and they are not happy about it.

“Well…