Shares of the Singapore company at last check fell 3.4% to $40.45. Shares of Tripadvisor, Needham, Mass., were off 1% at $43.
Sales by Trip.com are expected to occur in multiple tranches throughout 2021, the two companies said.
Under the companies' joint venture agreement, Trip.com relinquished the right to have its chief executive, Jane Sun, sit on Tripadvisor's board. Sun will continue to serve on the board, subject to the typical shareholder voting process, they said.
The two companies had entered their partnership in November 2019.
On Tuesday, Trip.com and Tripadvisor agreed to expand the partnership to include the subscription service Tripadvisor Plus.
"Initially, Trip.com will provide access to preferential pricing on at least 10,000 properties to benefit the Tripadvisor Plus offering," the two companies said in a statement.
"We continue to value our strategic partnership with Trip.com, inclusive of our joint venture in China, and appreciate Jane's ongoing contributions to our board," Stephen Kaufer, president and chief executive of Tripadvisor, said in a statement.
"We look forward to expanding Trip.com's presence on our platform over time," Kaufer added.