Last week, Bill Pascrell Jr., a Democratic representative of New Jersey, publicly denounced Ticketmaster for offering marked-up tickets for a Springsteen concert through its secondary ticket marketplace, TicketsNow.com, when tickets were still available at face value. After news of the planned merger broke, Mr. Pascrell called for the House Judiciary Committee to hold hearings.

“There is an incredible potential for abuse when one company controls the primary and secondary market for concert tickets,” Mr. Pascrell said in a letter to the committee. “That potential will surely be magnified exponentially should one company be able to control every aspect of recording, record sales, licensing, venue ownership and ticket sales.”

The rationale for the deal does not appear to be cost savings. Thomas Weisel Partners, for example, estimated that it would lead to just $50 million in annual savings, about 1 percent of combined operating costs.

The combined company, though, is expected to make the case that it will be better able to market its artists and fill stadiums. But the deal also appears to be aimed at eliminating competitive threats that each poses to the other, particularly in the ticketing business.

Live Nation has started a ticketing arm, making it an intruder on Ticketmaster’s main turf.

This so-called horizontal aspect of the merger could be the most important antitrust issue, lawyers who specialize in such matters say. Regulators are normally reluctant to approve a deal that kills off a potential competitor in an industry, in this case ticket sales, that has lacked much competition.

In addition, both companies have been moving into artist management. Live Nation has signed recording and touring deals with Jay-Z and Madonna; last fall, Ticketmaster acquired Front Line Management, the largest artist management firm.

At the same time, record labels have been trying to reach deals with artists that include a cut  for the labels  of revenue from touring and merchandise. Historically, record labels have not had access to those revenue streams, but in recent years profits and revenue from selling music from CDs have plummeted, and labels have been forced to seek new ways to make money.

The merger could present a major competitive threat to record companies in signing artists. David Joyce, an analyst at Miller Tabak & Company, said in a research note that the rationale for the deal could “include a desire by both companies, which now each have varying degrees of artist management contracts, to have greater bargaining position to potentially woo more artists away from the traditional label companies.”