NEW YORK, Dec 6 (Reuters) -

Zoom Video Communications was the bidder that was rebuffed by call center software firm Five9, according to a person familiar with the matter.

On Tuesday, Five9 said it had been approached with a takeover offer, without naming the bidder, and said it had decided not to pursue a transaction.

The source, who requested anonymity because the discussions are confidential, said the unnamed party rebuffed by Five9 was Zoom.

Both Five9 and Zoom did not immediately respond to requests for comment on Wednesday.

The recent approach from Zoom came about two years after shareholders voted against its proposed $15-billion-buyout of Five9.

Five9's shares, which rose as much as 16% on Monday, were trading at $81.5 on Wednesday, having erased all the earlier gains. Zoom's shares were trading at $70.65, giving the company a valuation of $21.5 billion.

Zoom's market value peaked in October 2020, as it became the poster child of the pandemic era after its video conferencing service was widely adopted in businesses and schools across the world.

However, as the world emerged from the pandemic and people started returning to offices for in-person meetings, Zoom's growth stalled. By November 2021, its market capitalization had fallen about $100 billion from its peak.

Zoom has sought to overcome the slowdown in the growth of its video-conferencing platform by offering a broader range of software tools, especially business collaboration software, to large corporations. Some of those efforts are starting to pay off; - after reporting revenue growth during the June quarter, Zoom forecast third-quarter profit above analysts' expectations.

Five9, whose call center software is used by more than 2,000 clients across the globe, counts companies like Alaska Airlines and Wyndham Hotels & Resorts among its customers. (Additional reporting by Arsheeya Bajwa in Bengaluru; Editing by Shailesh Kuber and Leslie Adler)