(Bloomberg) - Peter Deutsch hit it big bringing affordable Australian wine to the U.S. Then he poured a fortune into a troubled Chinese stock. And when his brokerage stood in his way, he fought back.

As Peter Deutsch sat in his spacious lakeside getaway in upstate New York one steamy July morning, the last thing on his mind was relaxing. The wealthy wine merchant was on a risky mission. He’d decided to buy control of a troubled Chinese company and then float a rescue plan. To do that, he’d have to snap up at least 5 million shares of its thinly traded stock in a matter of days. It was either that or kiss goodbye the $40 million he’d already invested.

With the waters of Lake George gently lapping onto his property, Deutsch turned to his iPad, opened his brokerage account, and tapped “buy.” Bingo. He picked up a few thousand shares. He tapped “buy” again. Nothing. Figuring it was a glitch, he reached for the phone. “What’s going on, guys?” he recalls asking one of his reps at Fidelity Investments. “I’m putting through important trades here.” The rep, he says, didn’t have a clue.

Deutsch says his unease turned to shock later that day when he fielded a call from a Fidelity employee he’d never spoken with before. Deutsch remembers the man informing him that Fidelity was “uncomfortable” with his purchases of China Medical Technologies, a Beijing-based maker of cancer-treatment devices. Effective immediately, the man told Deutsch, he could no longer buy the stock.

And with that, a hefty slice of his family’s net worth was toast.