One afternoon last month, Chad Nedohin, a part-time pastor and die-hard supporter of Donald J. Trump, put on a pirate costume, set up his microphone and recited a prayer.

Mr. Nedohin was opening his latest livestream on the right-wing video site Rumble, where he has about 1,400 followers who share a devotion to Trump Media & Technology Group, the former president’s social media company.

“Faith comes from hearing — that is, hearing the good news about Christ,” said Mr. Nedohin, 40, his face framed by fake dreadlocks under a pirate-style hat.

Mr. Nedohin and his viewers were waiting for the results of a merger vote that would determine whether Mr. Trump’s company could start selling stock on Wall Street. Soon the news about Trump Media arrived via an audio feed: It was going public.

Mr. Nedohin raised his arms in celebration. A few minutes later, he cut to a video of a rocket blasting into the sky, with Mr. Trump photoshopped onto it. “We are holding Trump stocks,” he declared. “We are now financial investors in him.”

Mr. Nedohin is one of hundreds of thousands of amateur investors who own shares of Trump Media, convinced that its sole platform, Truth Social, will become one of the world’s most popular and profitable social media sites. In recent months, tens of thousands of Trump fans have tuned into Mr. Nedohin’s webcasts, where he exhorts viewers to invest in the company, arguing that “Trump always wins in the long run.”