Airbnb’s exponential growth in the U.S. is being driven by an increase in hosts renting out multiple units and hosts offering entire homes, according to a report by CBRE Hotels’ Americas Research.

The report, issued Thursday on behalf of the American Hotel & Lodging Association, states these trends are especially evident in Airbnb’s top 13 domestic markets (Austin, Boston, Chicago, Los Angeles, Miami, Nashville, New Orleans, New York, Oahu, Portland, San Francisco, Seattle, and Washington, D.C.)

Airbnb is now valued at an estimated $31 billion after its latest fundraising round.

According to the research, hosts in the U.S. with two or more unit listings generated more than $1.8 billion in Airbnb revenue in 2016, which accounts for some 32.1 percent of Airbnb’s total U.S. revenue from October 2015 to 2016.

Revenue from this type of host grew at a faster rate than any other type of Airbnb host,. The report pegs the revenue increase at 89 percent year over year in the top 13 markets.

The majority of Airbnb hosts in the U.S. are also renting out entire homes, rather than sharing their homes with guests. The study said 63.9 percent of hosts in the U.S. are renting out an entire home unit, and they are responsible for generating 81.1 percent (about $4.62 billion) of Airbnb’s total U.S. revenue for 2016 ($5.69 billion).

The report was commissioned by the American Hotel & Lodging Association (AH&LA), a hotel industry association which has long battled Airbnb. The data CBRE used to compile the report came from Airdna, a company that used Web-scraping software to collect data on Airbnb from October 2014 to September 2016.

In putting the report together, CBRE said it isolated multi-unit, entire-home hosts and excluded data for shared and/or private room listings, unique property types (treehouses, igloos, etc.), and those listings that required a 30-day minimum stay. CBRE said it also only looked at active units, and excluded listings that did not have a single booking over the previous month; it said inactive listings accounted for half of Airbnb’s total listings in the U.S.

‘That’s Not Homesharing. It’s a Business’

During a conference call to discuss the CBRE report’s findings, AH&LA president and CEO Katherine Lugar said, “Today’s report shows, conclusively, that the company [Airbnb] is talking out of both sides of their mouth. They say they are against commercial operators, but they are enabling them to proliferate faster than any other type of host.”

Lugar, in her opening comments, wanted to demonstrate the difference between “traditional homesharing” where a host invites a guest to stay with her in her own home while she is present, versus the commercial use of hosts who have multiple units and are essentially running lodging businesses.

She said, for example, in Washington, D.C., 24 percent of the company’s revenue comes from hosts who have more than 20 units each. “That’s not homesharing. It’s a business,” Lugar said.

“Today, we call on Airbnb to hold true to their words to join us in the fight to take down illegal hotels form their platform. It’s time for them to move beyond just words and take real concrete action.”

A spokesperson for Airbnb said of the report, “This misleading, inaccurate report was bought and paid for by the big hotels and is the latest example of the industry’s willingness to say and do anything to protect their record profits, preserve their ability to price gouge consumers and squash their competition.

“As the AH&LA already knows, many of their member inns, motels, and hotels list rooms on our platform, so these are included in the very data on ‘commercial’ listings the big hotels seem so concerned about.”

So, Can We Trust This Data?

This is not the first time that AH&LA and Airbnb have entered into battle with one another.

Last year, AH&LA commissioned research examining the growth of commercial operators on the Airbnb platform and other short-term rental companies as well, releasing a series of reports about the growth of full-time hosts and hosts with multiple unit listings, in conjunction with Penn State University.

Around the same time last year, CBRE also published its own research on Airbnb’s growth and size in the U.S, also using Airdna data.

Airbnb countered the AH&LA/Penn State reports from last year, however, often saying that there was a difference between advertised listings and listings that are actually booked.

In this new CBRE report, researchers acknowledged that before October 2015, companies like Airdna could better determine booking data from Airbnb, and to know “the difference between a booked unit and a blocked unit,” CBRE Hotels’ Americas Research senior economist Jamie Lane said. “Starting in October 2015, that number had to be estimated because of an algorithm they [Airbnb] developed.”

This report, as well, doesn’t seem to make very clear distinctions between actual bookings and listings. It does define active versus non-active listings however.

Lane said, “When we classified revenue generated by multi-unit hosts we only counted that host as multi-unit if they had two or more units on the site being rented on any given month. If hosts had multiple units on the site and removed theirs so they only had one, that revenue only counted when they had more than two. We took a very conservative approach.”

Later, when asked if the CBRE/Airdna data was reliable, Lane said the numbers published in the CBRE report “were very close to what Airbnb was reporting,” and he noted that the numbers for New York City, in particular, closely matched the data published by Airbnb in conjunction with the announcement of the company’s “One Host, One Home” policy.

Lugar also noted that Airbnb’s own data are not always a reliable source as well, citing its “purge-gate” incident from 2015 in which the company removed approximately 1,500 listings from commercial operators in New York City right before it released data about its operations in the city. Because of this, what Airbnb presented as a snapshot of the company’s business activity in November 2015 was inaccurate, as it downplayed the number of Airbnb hosts with multiple listings.

Are Regulations in New York City and San Francisco Working?

This CBRE report also found that revenue growth for entire-home listings in the top 13 U.S. markets grew an average of 76 percent from October 2015 to September 2016. In some cities, revenue growth from entire home listings was very significant: Nashville (283 percent); Oahu (187 percent); New Orleans (144 percent).

However, two cities in particular, actually saw slower revenue growth from entire-home listings: San Francisco (57 percent) and New York City (39 percent). The share of the market from multi-unit Airbnb hosts in those cities also declined, unlike the other 11 cities isolated as top markets. In New York, that market share declined 7.1 percent and in San Francisco, there was a 4.6 percent drop.

While CBRE researchers wouldn’t confirm a correlation between this data and the effectiveness of recent regulatory activity taking place in those two cities, Lugar said the data implied that regulatory actions were having an impact.

“When you look at the data in the CBRE report where cities have taken strong actions like in New York or San Francisco, those laws are working to crack down on illegal hotels. … That’s why we’re calling on lawmakers in every level of government to protect neighborhoods and guests,” Lugar said.

Airbnb and its peers are currently suing the City of San Francisco for implementing stricter penalties for homesharing platforms that allow hosts in violation of the city’s short-term rental laws to advertise on those sites.

And in New York City, the city recently updated its short-term rental laws to include steep fines for hosts who advertise illegal units on platforms like Airbnb and HomeAway.

Another possible reason for these numbers not mentioned by AH&LA or CBRE is the fact that both cities are also two of the more mature markets for Airbnb where it has a large concentration of listings. In San Francisco, according to this data, there are 20,078 unit listings, and in New York, Airbnb’s No. 1 market in the U.S., there are 73,303. Los Angeles is Airbnb’s second largest U.S. market with 45,001 unit listings.

Photo Credit: A midtown Manhattan property offered through Airbnb. A new research report says the majority of Airbnb's U.S. listings are for entire homes, and a growing number of those listings are being operated by hosts with multiple listings. Airbnb