Shares of Oklo Inc. (OKLO) plummeted 5.32% in after-hours trading on Wednesday, following the company's announcement of a proposed $400 million public offering of common stock. This sharp decline came on the heels of a significant rally earlier in the day, where Oklo shares had surged nearly 30% to close at $68.03.

The nuclear technology startup, backed by Sam Altman, saw its stock soar during regular trading hours after revealing it had been conditionally selected to provide power to Eielson Air Force Base in Alaska. Oklo was issued a Notice of Intent to Award by the Defense Logistics Agency to supply nuclear energy using one of its Aurora powerhouses. This news had initially propelled the stock to all-time highs, with investors reacting positively to the potential long-term power purchase agreement with the U.S. Air Force.

However, the mood shifted dramatically in extended trading when Oklo announced its plans for a $400 million public offering of common stock. The company stated that it intends to use the net proceeds for general corporate purposes, working capital, capital expenditures, and potential future investments. Goldman Sachs & Co. LLC and BofA Securities are leading the offering, which is expected to close on June 16, 2025, subject to customary conditions. The sudden influx of new shares into the market likely sparked concerns about dilution among existing shareholders, triggering the after-hours sell-off.