Setting aside that people would doubt it's real...
MS owns less than 200k Bitcoin. 200k out of 21m is maybe 1% of total supply. If you consider that out of the 21m a lot of them might be lost forever it's still probably less than 2% of total supply.
The exchangerate between Bitcoin and fiat has a volatility where 2% is just a normal tuesday. It probably wouldn't be noticeable.