This year will see a new record set for investment in the PropTech sector. But where are the savviest tech investors putting their capital?

According to data from CB Insights, more than $1.5B has been invested in PropTech companies so far in 2017, and it expects $3.4B to be invested this year in total, a 25% rise on 2016.

The company has also drilled down into the companies being backed by what it calls "smart money." It picked a group of 24 venture capital firms that are the most successful investors in tech in general, based on the value of their portfolios and the returns achieved. The names include Sequoia Capital, Andreessen Horowitz and Redpoint Ventures.

“Top smart money funding areas for real estate tech include mortgage tech, crowdfunding and tech-enabled brokerage firms,” CB Insights said in a report, Build or Buy? Construction Tech vs. Real Estate Tech Startup Deal Activity.

Andreessen Horowitz is the lead smart money investor in the sector with investments across seven real estate tech companies.

Here are the four companies that have received the most investment from smart money investors.

Cadre

Cadre was started by Jared and Josh Kushner. It is a a technology-based online platform to allow family offices better access to real estate investments. Cadre is backed by four smart money firms: Andreessen Horowitz, Founders Fund, General Catalyst and Khosla Ventures. It is one of the four best-funded PropTech startups, having raised $383M.

Zumper

Zumper is an apartment rental platform that aims to make it easier for tenants to discover and lease apartments. Based on direct data feeds and partnerships with landlords, brokers and property managers, Zumper offers renters real-time, curated listings, and also streamlines the lead generation process for landlords and brokers.

Zumper is backed by four smart money investors: Kleiner Perkins Caufield & Byers, Greylock Partners, New Enterprise Associates and a16z. It has raised $37M.

OpenDoor Labs

OpenDoor is looking to provide a new source of liquidity in the resi market. Homeowners can visit Opendoor.com, receive a guaranteed offer and complete the sale online without a broker, if they like the price offered. It has received a huge amount of funding, $320M. Its smart money investors are Khosla Ventures, True Ventures and New Enterprise Associates.

Blend

Blend is a mortgage tech product that provides a platform to make the process of finding a mortgage easier for homebuyers and easier to provide for lenders, streamlining the mortgage process. It has raised $60M and its smart money investors are Andreessen Horowitz, Founders Fund and Lightspeed Venture Partners.