"It is clear that this merger raises serious competitive concerns warranting thorough scrutiny," wrote Sen. Herb Kohl to Christine Varney, head of the Justice Department's antitrust division, according to Reuters.
Kohl wrote that the deal would create "an enormous, vertically integrated entertainment giant, which will control everything from artist management, concert promotion, concert venues, and merchandise sales to primary and secondary market ticket sales."
The U.S. House of Representatives went even further in terms of casting doubt on the merger.
"We see little to commend this transaction," wrote Rep. Bill Pascrell in a letter signed by 50 members of the House of Representatives. The letter further cited "competitive harm in the ticketing and other industry markets" because of the deal.
In mid-July, Live Nation head Michael Rapino said he still believed the merger would close by end of the year.