Elizabeth Warren joins a group of Senators calling on the FTC to investigate the short-term rental business

Airbnb is once again under the microscope.

A trio of Democratic Senators today called on the Federal Trade Commission to investigate how companies such as Airbnb are impacting the housing market.

Senators Brian Schatz, D-Hawaii, Elizabeth Warren, D-Mass., and Dianne Feinstein, D-Calif., urged the FTC to look into the fast-growing short-term rental market, expressing concerns that these services might be making housing more expensive and harder to find.

"We are concerned that short-term rentals may be exacerbating housing shortages and driving up the cost of housing in our communities. We have also read troubling reports of racial discrimination on some short-term rental platforms," Schatz said in a letter to FTC Chairwoman Edith Ramirez.

The Senators aren't concerned with a family of four that occasionally rents out a room to earn extra cash. Rather, they urged the FTC to focus its attention on commercial uses of services like Airbnb, HomeAway, VRBO and Flipkey.

A New York State Attorney General's examination of Airbnb found that the service had turned apartments into transient hotels. Subpoenaed documents revealed that while commercial property owners accounted for a scant 6 percent of Airbnb hosts in New York City, they collected a disproportionate 37 percent of the revenue.

That suggests renters may be getting displaced.

"To assess the use and impact of the short-term rental market, we need reliable data on the commercial use of online platforms," the Senators wrote.

Airbnb spokesperson Chris Lehane issued a statement noting that the vast majority of hosts across the country are middle-class people who depend on home-sharing to bolster their incomes. One study of 10 of the largest cities in the U.S. found that 51 percent of hosts depend on this extra money to make ends meet — with 13 percent saying they've managed to fend off foreclosure or eviction because of homesharing.

"We welcome any opportunity to work with lawmakers and regulators who want to learn more about how home sharing helps the middle class address the issue of economic inequality," Lehane said.

Here's the letter:

This article originally appeared on Recode.net.

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