OpenAI is a corporation, so their losses do not flow up to their owners.
Their investors, if publicly traded like Microsoft do have to take write-downs on their financial statements but those aren't realized losses for tax purposes. The only tax "benefit" Microsoft might get from the OpenAI investment is writing off the amount it invested if/when OpenAI goes bankrupt.
Their investors, if publicly traded like Microsoft do have to take write-downs on their financial statements but those aren't realized losses for tax purposes. The only tax "benefit" Microsoft might get from the OpenAI investment is writing off the amount it invested if/when OpenAI goes bankrupt.