May 28 : AI infrastructure firm Nebius Group's shares climbed over 10 per cent in premarket trading on Thursday, after Situational Awareness, a fund run by a former OpenAI employee named Leopold Aschenbrenner, became its biggest shareholder. The gains put the stock on track to open at its highest in over two weeks. The fund reported a 5.6 per cent stake in Nebius, worth nearly $2.6 billion as of Wednesday. Situational Awareness managed $13.67 billion as of March 31, representing 148 per cent