May 3 (Reuters) - Expedia shares sank about 9% in premarket trading on Friday, after the online booking firm cut its annual forecast for revenue growth due to weakness at its vacation rentals brand Vrbo.

The company, which is known for its three brands Expedia, Hotels.com and Vrbo, projected full-year revenue growth in the mid-to-high-single digit percentage range late on Thursday, down from a prior forecast of double-digit growth.

The company had migrated its Vrbo brand to the Expedia platform along with the rollout of its consolidated loyalty program covering all three brands, in a bid to allow customers to book across nameplates under one platform.

While Expedia hoped for a profit boost from the re-platforming of Vrbo, it said the brand was seeing a slower rebound, which weighed on overall bookings.

"We had pulled back on Vrbo marketing in the second half of last year... And while we have been ramping that spend and the product has been improving, we have seen a slower-than-expected recovery," outgoing CEO Peter Kern said.

At least seven brokerages cut their price targets on Expedia, with Piper Sandler downgrading the stock to "neutral" from "overweight".

"The near-term growth trajectory is uncertain as the company struggles to sustainably improve growth and materially raise traffic at two of its core brands (Vrbo and Hotels.com)," Wedbush analysts said in a note.

Shares of Expedia trade about 25.32 times their forward profit estimates, below the 29.44 multiple for rival Booking Holdings, which on Thursday topped market estimates for quarterly profits.

"Expedia's in a tough spot. The broader business is growing ... however, Vrbo is displaying issues which may be more difficult to fix than management is letting on," brokerage RBC said.

(Reporting by Pratyush Thakur in Bengaluru; Editing by Arun Koyyur)