Hashicorp was sold for 6.5B to IBM.

Another thing - when it went public it was valued at 13B and Hashimoto owned 8.5% of it according to the filing.

So, depending on when he sold or converted his shares it is pretty plausible that he got a billion.

Shockingly I believe billionaire with a B. They timed the acquisition nearly perfect in terms of market conditions. Tres comma club!!!

was that big