US retailers’ same-store sales in June about matched analysts’ estimates, with discounters like TJX Cos. topping expectations. Concerns about the economy have many consumers shopping at discount chains. TJX, which owns T.J. Maxx and Marshalls, posted a 7 percent gain in same-store sales. It beat analysts’ average estimate for a 3.7 percent sales increase. The Framingham-based retailer said profit this year may be as much as $2.39 a share, up from a previous forecast of up to $2.37.