Microsoft witnessed a historic surge in its stock on Monday, November 20, following the announcement of Sam Altman, former CEO of OpenAI, joining the company to lead its artificial intelligence innovation division.

The tech giant’s shares soared to $377.10 during Monday morning trading, marking a significant increase. To achieve an all-time high close, the stock would need to conclude above $376.17.

This surge in Microsoft’s stock price occurred after Altman’s appointment, which came on the heels of his departure from OpenAI following a boardroom upheaval. Microsoft, being the largest stakeholder in OpenAI with a $13 billion investment, witnessed a 1.7% decline in its shares when Altman was ousted from his position at the AI firm.

Microsoft stock hits all-time high after the company hired former OpenAI CEO Sam Altman

Notably, Greg Brockman, a co-founder of OpenAI who departed alongside Altman, is also joining Microsoft.

Altman’s return to Microsoft ended speculation surrounding his potential comeback after the tumultuous events at OpenAI. The transition also saw Emmett Shear, former CEO of Amazon-owned streaming service Twitch, stepping in to temporarily replace Mira Murati as OpenAI’s chief technology officer.