Tiffany & Co . slightly downgraded earnings expectations for the second quarter ending July 31, saying earnings would likely fall to 23 and 25 cents a diluted share. The New York jewelry retailer said in May that earnings “could approach last year’s level” of 26 cents a share, assuming that sales at U.S. stores open at least a year were equal or better to year-earlier results. Analysts had been expecting Tiffany to post earnings of 25 cents a share, according to Thomson Financial/First Call. Yesterday, Tiffany blamed “restrained customer spending” and a reduction in average transaction size. It added that U.S. same-store sales are tracking “a few percent below the prior year.” For the third quarter, Tiffany expects to post net earnings roughly equal to last year’s and “healthy sales and earnings growth in the fourth quarter.” The company plans to report second-quarter results Aug. 16. Tiffany issued its statement after 4 p.m. In 4 p.m. New York Stock Exchange composite trading, Tiffany shares fell 47 cents to $34.73.