By Avi Salzman

Nuclear stocks have soared in recent days, as the Trump administration makes nuclear energy a centerpiece of America's trade talks with countries including the United Kingdom. The gains have been lucrative for insiders at the highest flying nuclear firms, and some of them have sold stock as the shares rallied.

Securities filings show insider sales at upstart nuclear reactor developers Oklo and NuScale Power. Both stocks were up by more than 20% on Friday, adding to a string of seemingly unstoppable gains. Oklo hit a new all-time high on Friday, and the stock is up more than 1000% since its debut last year.

Bullish investors expect both companies to be early winners in the race to commercialize new kinds of nuclear reactors.

In recent days, executives at Oklo have sold stock or announced their intention to sell.

This Wednesday and Thursday, Oklo Chief Financial Officer R. Craig Bealmear filed notices of intention to sell 100,000 shares of stock, worth about $9.4 million. Bealmear acquired the shares by exercising stock options. As of the company's proxy statement in April, he owned 508,025 shares, which excluded certain restricted stock units but included stock options that had vested or were set to vest in the next 60 days.

One of the Oklo executives who sold missed the latest rally. On Sept. 5, William Goodwin, chief legal and strategy officer, sold 41,387 shares at an average price of $70.09, for a total value of $2.9 million, according to an SEC filing. He no longer holds any stock in the company, the filing says.

The company didn't respond to a request for comment on the sales.

Oklo, based in Santa Clara, Calif., is developing a new kind of small reactor that it says can be built for less money than the large reactors that dominate the nuclear industry today. The company has said it expects to break ground on its first nuclear reactor in Idaho in the current quarter, and begin commercial operations by late 2027 or early 2028.

The company has already attracted support from some boldfaced names. OpenAI CEO Sam Altman was previously its chairman, and current U.S. Secretary of Energy Chris Wright was on the board until he stepped down after joining the government. The Department of Energy selected Oklo and a subsidiary for a total of three pilot nuclear projects.

But the company has several milestones to achieve before it can start operating and generating revenue. Oklo doesn't yet have a license to operate the reactor, and was denied a permit by the Nuclear Regulatory Commission in its first attempt.

Executives at NuScale haven't sold stock in recent days, based on the latest filings, but a major corporate shareholder has. Industrial company Fluor, which was the largest individual shareholder in NuScale as of March, sold 2.5 million shares for about $96 million in several transactions from Tuesday through Thursday, according to securities filings.

Fluor continues to own 12.5 million Class A shares, according to the filing. Fluor received more than 100 million of NuScale's illiquid Class B shares as part of NuScale's public listing through a special purpose acquisition company, or SPAC.

Fluor recently began to exchange that Class B stock for tradable A shares, and has now begun to sell them. Fluor said on its latest earnings call that it planned to "monetize" some of its NuScale stake.

Neither NuScale nor Fluor returned messages seeking comment.

NuScale is the first small reactor company to receive a U.S. license to operate its reactor but has struggled in its attempts to commercialize the technology.

Write to Avi Salzman at avi.salzman@barrons.com

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September 19, 2025 16:18 ET (20:18 GMT)

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