The PropTech market is showing signs of maturing venture capitalists increasingly fund more established real estate tech companies during later rounds of funding, instead of the initial seed stage.

Several factors may be playing into this trend, The News Funnel reports, including the emergence of a “winner takes all” movement where investors are concentrating on late-stage funding rounds for companies like Airbnb, WeWork, VTS and Cadre — all of which are expected to dominate in the industry — more than on startups in need of seed capital.

VC firms poured $12.6B into real estate tech companies in 2017; that's triple the $4.2B injected in tech platforms in 2016. In the fourth quarter, an estimated 31% of investors made investments beyond the series A level. This rose from only 19% during the second quarter, Commercial Observer reports.

Angel investors, though growing in the U.S., are becoming increasingly careful about how they invest their money. This is making it difficult for early stage companies, which are often considered risky ventures, to obtain funding. The News Funnel reports the rise in the popularity of cryptocurrencies could also be a cause of the decline in seed stage funding, as many early stage investors have elected to invest their capital in digital currencies like bitcoin rather than CRE tech startups as of late.