I can't prove any of this, you'd have to take my word for it! I guess if we ever go public in N years (not saying we are, but _if_), you'll see for yourself on historical results. :)
(I have no affiliation with HashiCorp.)
The only source I found was https://www.hashicorp.com/blog/2017-year-in-review which just says the company "can be successful", not that it is making money.
From Mitchell himself - at the very least they are growing very quickly. For all the complaining about "pricing pages", I think hashicorp is doing the right thing. Focus on selling to the big dogs who can give you a sustainable business and don't cloud your pipeline with smaller shops who wish to shop around.
So here we are slacking postman collections back and forth on our current year mac books.
It's probably one of the next companies to be acquired in the coming years.