The Securities and Exchange Commission is investigating stock activity related to the attempted $450 million takeover of Grumman Corp. by LTV Corp.

A Grumman spokesman confirmed that the agency is investigating some aspect of the takeover battle. Neither the spokesman for Grumman nor an attorney for the firm would confirm or deny that the investigation involved certain stock purchases.

"I can't comment," said attorney Raymond Falls.

Grumman spokesman Sandy Jones said that Grumman has not "been in collusion" with anyone, noting that he had received several calls speculating about the subject of the inquiry. "There is an SEC investigation," he said but he disavowed any specific knowledge of what the agency is investigating. SEC officials could not be reached for comment.

Grumman and its pension fund have bought substantial amounts of stock in an attempt to thwart LTV's bid for the Long Island-based aerospace company.

LTV announced its takeover bid on Sept. 23. The merger, if successful, would combine two major Pentagon suppliers. Since the merger proposal a federal judge has temporarily halted it, scheduling a hearing on whether the merger would violate the nation's antitrust laws.

The Labor Department filed suit earlier this week against trustees of the Grumman pension plan for using pension fund assets to buy Grumman stock as part of Grumman's strategy to block the takeover.

LTV announced on Thursday that it would extend its offer to buy Grumman stock from yesterday, when it was scheduled to expire, to Nov. 3.