I’ve recently learned that the investment actions of reclusive 89-year-old billionaire Kirk Kerkorian have caught the eyes of the Securities and Exchange Commission.

The SEC’s chief interest centers on Mr. Kerkorian’s gigantic 56 millionshare (or 9.9%) stake in General Motors and, more specifically, some short selling in GM stock before the release of negative news regarding his holdings in the automaker.

Here’s the background: On September 28, it was announced that Mr. Kerkorian’s investment arm, Tracinda Corp., had sent a letter to GM that it had made a filing with the SEC to the effect that Mr. Kerkorian was prepared to raise his GM stake to 12% through the acquisition of as many as 12 million more shares or about 2% of the stock. In response to that disclosure, GM’s shares rose moderately on that day.

More than a week later, on October 6, it was announced that Mr. Kerkorian, disenchanted with the automaker’s decision to end its alliance talks with Renault and Nissan, had scrapped his plans to buy those additional GM shares. At the same time, it was disclosed that Jerry York, Mr. Kerkorian’s representative at GM, had resigned from the board.

It wasn’t the kind of news Wall Street wanted to hear. And in response, GM’s shares ran into brisk selling and fell 7% on the day.

What apparently piqued the SEC’s interest, it’s believed, was talk of some short selling in GM prior to Mr. Kerkorian’s change of heart about acquiring more shares. In other words, the inference is there may have been a leak on Mr. Kerkorian’s decision.

The SEC clearly appears interested. Last week, the agency, I’m told, rang up at least two hedge funds to inquire about their recent short selling in GM. The manager of one of them, a New York fund and one of the city’s more successful short sellers, acknowledged a call from the commission, but he vigorously defended his short sale as “a legitimate trade based on the well-known fact that GM is a troubled company.”

He further noted that his short sale was not new, but an expansion of an existing short position in GM.

He wouldn’t discuss the size of his GM short bet. Nor would he respond when I specifically asked whether he had heard that Mr. Kerkorian had a change of heart about buying more GM shares.

Presumably, the SEC, given its inquiries in the investment community, is thought already to be examining the action in GM’s shares and options around the time in question.

The nature of the SEC’s interest, whether it be associated with a formal investigation, an informal inquiry, or simply a matter of fishing for information, could not be immediately determined. Asked about the SEC’s GM interest, an SEC spokesman declined to comment, other than to say, “We don’t reply to such questions.”

On the surface, it seems the SEC would be hard pressed to make a case on a GM short sale, what with the latest short interest figures showing a massive GM short position of 64 million shares.

Mr. Kerkorian, a high school dropout and the son of an Armenian immigrant who has amassed an estimated net worth of $10 billion, could not be reached for comment.

I rang up GM for comment, but two members of GM’s public relations staff said they had never heard of Mr. Kerkorian. Perhaps they should brush up on their company’s more important investors. A spokeswoman for Tracinda didn’t return calls seeking comment.

GM aside, I’ve also learned that securities industry regulators have recently embarked on at least eight new and unreported stock trading investigations, five by the SEC, one by the market regulation department of the New York Stock Exchange, and two by Nasdaq.

These regulatory bodies have already sent letters to brokerage firms, soliciting the names of customers who traded in the shares and options of the various companies.

Among the better-known stocks from this group whose trading is being probed are:

• Labranche & Co., one of the oldest and largest market-making firms, which handles trading in more than 500 Big Board companies.

• Oxford Industries, a leading maker of private-label clothing that has licensing agreements with such wellknown designers as Tommy Hilfiger, Geoffrey Beene, and Oscar de la Renta.

• Boyd Gaming Corp., a leading casino operator in Las Vegas.

• ATI Technologies, a top supplier of computer graphic chips and boards.

Rounding out the eight stock trading investigations are ADVENTRX Pharmaceuticals, Advinar Pharmaceuticals, WestBank Corp., and Pixelplus Co. Ltd.

dandordan@aol.com