Likely. Last year the foundation they're a part of received $25,000 in earmarked donations for Postgres which you can extrapolate over the 30 years it's been around to be a million-ish [1]. They've also received several million dollars in subsidies by starting as an academic project at Berkley in the 80s.

[1]http://www.spi-inc.org/corporate/annual-reports/