Venture capital investors are flush with cash, but they may want to slow down their spending.

U.S. venture firms have roughly $150 billion of funds available to invest in cash-starved startups, a little more than half of the $279 billion they have raised since 2014. That estimate of the VC industry’s “dry powder”—business slang for cash reserves—comes from an analysis of data from PitchBook and the National Venture Capital Association performed by Jon Sakoda, founder of the early-stage venture firm Decibel Partners. He estimates that about half of the dry powder is reserved for new investments, while the other half is for follow-on investments in startups VCs previously put money into, as the chart above shows.