So, here's the thing about being a pre-revenue nuclear energy company: you're going to lose money. A lot of it. The question is whether you're losing it in a way that gets you closer to actually building something. Oklo Inc. (OKLO) gave investors a fresh look at both sides of that equation Tuesday.

The company reported its fourth-quarter 2025 results after the bell, and the headline number was a loss of 27 cents per share. That was wider than the 16-cent loss analysts were expecting. For the full year 2025, operating losses totaled $139.3 million. Oklo was upfront about the fact that this spending isn't going to stop anytime soon. The company said "significant ongoing operating expenditures" will be necessary to develop its powerhouses and fuel fabrication facilities, acquire fuel, and expand its radioisotope business.

Putting some numbers to that outlook, Oklo expects total cash used in operating expenses for 2026 to be between $80 million and $100 million. The real big-ticket item, however, is investing activities, where it expects to burn through $350 million to $450 million next year. To fund all this ambition, the company isn't exactly running on fumes. It ended the period with approximately $788.45 million of cash and cash equivalents and another $439.53 million in marketable securities. That's a hefty war chest for a company that hasn't sold a single kilowatt-hour yet.

Now, for the more encouraging news buried in the earnings release. Oklo announced that the U.S. Department of Energy (DOE) approved its Nuclear Safety Design Agreement (NSDA) for Atomic Alchemy's Groves Isotopes Test Reactor in Texas. This approval comes under the DOE's Reactor Pilot Program and is a critical step in getting the facility licensed and built.

"With DOE's approval, we are making meaningful progress in the development of this isotope facility," said Jacob DeWitte, co-founder and CEO of Oklo. "This plant will help us gather critical data, refine our processes, and apply those lessons to subsequent licensing submissions and future deployments."

Think of it as a practice run. This isotope facility isn't the main event—Oklo's first commercial Aurora powerhouse is—but it's a crucial proving ground. The company broke ground on that first Aurora site in September and is still targeting its deployment for 2028. The data from the isotope reactor could smooth the path for the bigger project.

Investors seemed to be weighing the wider-than-expected loss against the regulatory progress. In after-hours trading Tuesday, Oklo shares were down 0.82%, trading at $60.15. The company's management team was scheduled to discuss the quarter further on an earnings call.

So, the story remains the same, just with updated numbers: Oklo is spending heavily to build the future of nuclear energy, one regulatory approval and groundbreaking at a time. The cash is going out the door, but the milestones, however incremental, are being checked off.