Stocks moved lower in midday trading Friday, following European markets into the red, as Greece’s future continued to look shaky after a breakdown in negotiations with the IMF. The IMF’s technical team returned to Washington from Brussels on Thursday after talks showed no progress. Discussions over further debt relief for Greece will continue at the political level, though those too have shown signs of a stalemate. To better news, consumer sentiment rose in June, rebounding from a six-month low in May. The University of Michigan’s gauge backs up retail sales data out yesterday that showed consumer spending making a comeback. Wingstop (WING) soared in its market debut, soaring more than sixty percent to just over $31 per share. And Twitter (TWTR) gave up most of its gains by midday. The social network had surged after CEO Dick Costolo announced he was stepping down from the position.