A U.S. investment fund is putting pressure on NEC Corp. to give up control of its ailing chip making unit by offering $1.25 billion for a 25 percent stake, the latest foreign shareholder to apply heat on what they see as

Electronics Corp. for about 154 billion yen ($1.25 billion), or 5,000 yen a share, a source close to the matter said on Wednesday.

That would be a 58 percent premium to the closing price of the world's No.11 chip maker prior to the offer.

NEC, which has repeatedly said it does not intend to sell its stake, is unlikely to accept the fund's proposal but may have to offer a restructuring plan to make NEC Electronics' shares rise to 5,000 yen, said Goldman Sachs analyst Ikuo Matsuhashi.

NEC will have to explain to its shareholders why it is rejecting the proposal, he said.

Overseas investors are becoming more vocal in corporate Japan, demanding better returns and triggering a backlash among Japanese stakeholders who associate foreign shareholders solely with short-term trade.

NEC Electronics shares have shed 32 percent since its listing four years ago. Analysts say the chip maker allocates too much of its resources to a wide array of unprofitable chips sold in small lots, and spends too much on research and development to design chips solely for parent NEC.

Perry Capital, NEC Electronics' third-largest shareholder with a 4.8 percent stake as of the end of March, has been urging NEC to cut its 70 percent holding in its chip unit to less than 50 percent to give NEC Electronics more independence.

The offer was made to NEC on condition that it give up majority control of NEC Electronics' board, the source said.

Perry Capital's offer of 5,000 yen represents an enterprise value seven times NEC Electronics' EBITDA forecast by seven analysts. That compares with an EV/EBITDA of 5.8 at Elpida Memory Inc., 7.1 at STMicroelectronics and 11.6 at Texas Instruments Inc.

NEC confirmed that Perry had offered to ownership structure, over time the company has the potential to achieve much better results and reach an intrinsic value of around 1,000 billion yen, Perry Capital, with $11 billion in assets, wrote in a letter to NEC and NEC Electronics.

Another U.S. fund, NWQ Investment Management Co., is also pressuring NEC to cut its stake in the chip subsidiary.

But such approaches have been largely ignored.

NEC has also refused past offers from chip makers and private equity firms interested in buying the loss-making chip unit, NEC executives say.

NEC President Kaoru Yano told reporters on Tuesday the parent company planned to keep its stake in NEC Electronics even after the chipmaker said it could be delisted by the Tokyo bourse because more than 75 percent of its shares are held by a small number of investors.

(Additional reporting by Nathan Layne and Aiko Wakao)