AT&T, Verizon Wireless, Sprint and T-Mobile, the four major cell phone competitors, are being questioned by the Senate Antitrust Subcommittee for their $.20 text messaging price increase. Senator Herb Kohl, chairman of the Antitrust Subcommittee, sent a letter on September 9 to the executives of the four cell phone companies, expressing concern for the 100 percent increase in text messaging. “These increased rates do not appear to be justified by any increases in the costs associated with text messaging,” Kohl’s letter said. “But may instead be a reflection of a decrease in competition, and an increase in market power, among your four companies.” Deborah Lewis, spokeswomen for Verizon, said her company would respond directly to the Subcommittee after the company evaluates the accusation.