The U.S. Senate's judiciary committee will examine the planned merger between insurance giants Highmark Inc. and Independence Blue Cross during a hearing next week in Philadelphia.

Sen. Arlen Specter, the GOP's highest-ranking member on the Senate Judiciary Committee, and Vermont Democrat Patrick J. Leahy, the committee head, announced the meeting yesterday. Though Mr. Leahy is the chair, Mr. Specter will preside over the full committee hearing, to be held at the auditorium at the National Constitution Center in Philadelphia's Independence Mall area. The meeting is scheduled for 9:30 a.m. Monday.

Of all the Senate committees, the judiciary committee has the broadest jurisdiction, and may review antitrust and monopoly issues, which happen to be two worries at the heart of the merger. A combination of Downtown-based Highmark and Philadelphia-based Independence would fuse the state's two biggest health-care insurers to create the third-largest health insurer in the country.

Together, the combined insurer would collect up to $16 billion in premiums and control more than half of the state's health insurance market -- a share of consumers that raises questions, if not skepticism, on both federal and state levels.

On the federal level, the Justice Department will be eyeing the deal. In Pennsylvania, the attorney general will review the merger.

Likewise, the state Senate Banking and Insurance Committee, headed by Republican state Sen. Don White of Indiana, will convene a hearing to discuss the merger, as well as twin House and Senate bills that would give the state's Insurance Commissioner and his department more authority to regulate such blockbuster deals.

Current law allows the Insurance Department to regulate for-profit subsidiaries of the two insurance giants, but not the master holding companies. The law, if approved, would be retroactive to Jan. 1, and Mr. White's office said Senate legal counsel believes that the law would withstand a constitutional challenge.

Joe Pittman, Mr. White's chief of staff, said his boss, a former insurance agent, is not necessarily opposed to the merger, but wants to make sure the combined company, as yet unnamed, wouldn't adversely affect the price of insurance premiums in Pennsylvania. "Competition is a good thing for the consumer," Mr. Pittman said.