* MISP holds nearly 40% of PNE - spokesman
* MSIP extends offer period by two weeks (Adds MSIP comment)
FRANKFURT, Nov 28 (Reuters) - The Morgan Stanley Infrastructure Partners (MSIP) fund has extended its offer to buy German renewable firm PNE AG by two weeks to Dec. 12, it said on Thursday.
MSIP's bid of 4.00 euros per PNE share, valuing the group at 306 million euros, has been rejected by top-10 shareholders ENKRAFT and Active Ownership Corporation.
ENKRAFT, which holds more than 2.9% of PNE, has said that a fair offer would be 6.90-7.10 euros per PNE share, valuing the firm at up to 544 million euros.
SdK, a shareholder group representing retail investors, has also said the bid is too low.
MSIP said it had scrapped a minimum acceptance level for the bid of more than 50% of PNE's shares. As of Nov. 27, the day before Thursday's original deadline, MISP had secured a stake of nearly 40%, a spokesman for the investor said.
"As an infrastructure investor with a very long investment horizon we're glad to support the company as a new top shareholder," the spokesman said.
Shares in PNE traded down 0.1% at 4.03 euros.
ENKRAFT said plans to delist PNE - which management will initiate if more than half of the group's investors accept the bid - should now be off the table.
"The plan of PNE's management to help Morgan Stanley become the majority shareholder of PNE has failed," said Benedikt Kormaier, managing director of ENKRAFT.
"By waiving the minimum acceptance condition Morgan Stanley underlines its willingness to become a large minority shareholder at PNE." (Reporting by Christoph Steitz; editing by Jason Neely, Kirsten Donovan)