Some reports have said Amazon's share of the online market is as high as 50 per cent, but others put the figures much lower. Critics say Amazon should be required to disclose more detail about its sales. Barry Lynn a leading authority on competition policy, at the Washington-based New American Foundation think tank, has called for an antitrust investigation into Amazon's US$13.7 billion Whole Foods takeover announced in June. "They dominate retail online," Lynn said. "That's huge power across the part of the economy where all the future growth will be." And longtime consumer advocate Ralph Nader said, "With every move of this Goliath, Amazon is inviting a thorough anti-trust investigation." "This company is breaking records for destroying Main Street and hollowing out communities through such mechanisms as predatory pricing, and for many years in the past, avoiding state sales taxes." Yet some experts are sceptical of an antitrust case against Amazon. "It's not an antitrust violation just to be dominant.