TAIPEI, April 23 (Reuters) - Taiwanese chipmaker United Microelectronics Corp (UMC) said on Wednesday that there was currently no ongoing merger activity, following reports the company and U.S.-based GlobalFoundries are considering a tie-up.

US-listed shares jumped 5.9% in premarket trading.

UMC and GlobalFoundries are looking into whether to merge, two sources familiar with the matter told Reuters last month.

A combined company would establish a larger U.S.-based firm with a global manufacturing footprint spanning Asia, the United States and Europe.

Asked about the reports on an earnings call, UMC Chief Financial Officer Chitung Liu said he did not want to comment on what he called market rumours, given such major news would have to come from an "official announcement".

"From UMC's perspective, we are consistently looking for strategic options to enhance shareholder value. Anything that can help increase our competitiveness and shareholder value we will certainly look into that," Liu said.

"There is no ongoing so-called merger activity right now," he added.

"It doesn't have to be a merger. There are many other collaborations we can still pursue," Liu said, without elaborating.