NEBIUS (NBIS) stock surged 5.02% in post-market trading on Monday, marking a significant 24-hour gain for the AI cloud infrastructure company.

The rally was driven by multiple positive catalysts. First, Nvidia Corporation disclosed a 9.3% passive stake in Nebius Group via an SEC filing, signaling strong institutional confidence from a leading AI chipmaker. Concurrently, the company announced the completion of a $775 million inaugural senior secured debt facility, which is collateralized by its deployed GPU computing infrastructure and long-term contracted cash flows. This financing addresses a key financial overhang and provides capital for expanding its AI cloud platform capacity.

Adding to the bullish sentiment, Freedom Capital Markets upgraded Nebius to a "Buy" rating from "Hold," citing an attractive entry point after the stock's recent pullback. The upgrade, combined with the successful debt deal and strategic investment from Nvidia, restored investor confidence in the company's growth trajectory within the competitive AI infrastructure sector.