Business travelers are increasingly booking stays through Airbnb and other home-sharing sites.
Airbnb said Monday that nearly 700,000 companies have signed up and booked rooms through its business travel portal, almost triple the number since last year.
Airbnb says 15 percent of its travel nights booked are for business travelers. That compares with 20 percent for Booking.com, which includes homes and hotels on its site.
SAP Concur, which handles travel and expenses for more than 43,000 businesses, says home-sharing is especially appealing when hotel rooms are in short supply. This month, it's adding Airbnb accommodations to its search options.
But home-sharing companies have a long way to go to catch up to hotels. Marriott International says business travel accounts for 70 to 80 percent of nights booked at its hotels.