Their revenues are growing incredibly fast. Yes, they started out in the intelligence sector, but since then they have typically been taking only one client in each new industry they throw their solutions at, e.g. finance, oil & gas, utilities. They look for some of the hardest problems in each industry and solve those and then move on to another industry trying to push their valuation as high as possible. Palantir actually rejects would-be customers who reach out to them if the potential customer is in an industry they have already tackled because they don't have the manpower to take on new challenges and also repeat solving of problems they have already solved. Most stories out there just cover their early work whereas they have been scaling by leaps and bounds. Some estimates put this amount of funding at 3% of their valuation.