NEW YORK ( TheStreet) -- Pinnacle Entertainment ( PNK) significantly missed second-quarter estimates, but shares are in the green as its margins improved. During the quarter, the regional casino operator swung to a loss of $49.3 million, or 81 cents a share, compared with a profit of $4.7 million, or 8 cents, in the year-ago period for Pinnacle. Excluding items, Pinnacle actually lost 14 cents a share, 10 cents worse than analysts' estimates of a 4-cent loss. Pinnacle's revenue rose 8.5% to $273.6 million from $252.3 million, but also fell short of Wall Street's forecast of $284.4 million. Still, J.P. Morgan analyst Joseph Greff reaffirms his overweight rating on the stock, viewing Pinnacle as a transition story. "We continue to believe that new CEO Anthony Sanfilippo and team will drive increased operating efficiencies and allocate capital prudently," he wrote in a note. Greff praises Sanfilippo for shelving the Sugarcane Bay project and instead focusing on Baton Rouge. Pinnacle's liquidity remains strong, with $200 million in cash and $375 million of availability under its revolver, with no debt due until March 2014. Shares of Pinnacle are gaining 3.7% to $11.42 in morning trading. -- Reported by Jeanine Poggi in New York. Follow TheStreet.com on Twitter and become a fan on Facebook.