Swing voter. (Wall Street West).

The fight for ultimate control of Hewlett-Packard Co., the Palo Alto-based tech giant contemplating a merger with Houston-based Compaq Computer Corp., is getting testier as the March 19 showdown approaches. In ads that ran in the Los Angeles Times and other national publications last week, H-P all but accused board member and founding family member Walter Hewlett of self-dealing.

Even by modern Wall Street standards, the ads raised a few eyebrows. Walter Hewlett is leading Hewlett and Packard family members who have come out opposing the proposed merger with Compaq, while Carleton "Carly" Fiorina, H-P chairman and chief executive, likely won't stay if the deal doesn't get done.

One of the key targets of the ad campaign is right here in Los Angeles. Capital Research & Management, the downtown-based money manager, is the largest shareholder in H-P (aside from the Hewlett and Packard families, who collectively own 18 percent). Capital Research owns $1.4 billion of H-P's stock, or about 3.54 percent.

That's a relatively small- percentage, but it looms huge in the close fight that is brewing, and Capital Research could be thought of as holding the swing votes. "You know it is close," said one insider last week. "Or else Carly wouldn't be running ads like that."

Chuck Freadhoff, spokesman for the press-shy Capital Research, declined comment. However, San Diego-based Brandes Investment Partners LP, a money-management with 1.3 percent of HP, last week came out against the merger.

Contributing columnist Benjamin Mark Cole writes about the local investment community for the Los Angeles Business Journal. His new book is "The Pied Pipers of Wall Street: How Analysts Sell You Down the River;" published by Bloomberg Press. He can be reached at [e-mail].