NEW YORK — Retailers are reporting sales gains for May that suggest Americans cautiously loosened their purse strings to take advantage of new styles and Mother’s Day promotions.

Major retailers including Target Corp., Costco Corp. and Limited Brands Inc. all posted healthy gains from a year ago.

Target and Limited both reported gains in a key measurement that topped Wall Street expectations. Costco also said revenue at stores open at least a year was up 4 percent. That was shy of the 4.3 percent analysts expected, but lower gas prices dragged down the number.

On Wednesday, Macy’s Inc. said revamped offerings pushed up the measurement 4.2 percent.

Revenue at stores open at least a year is a key measurement of retail operating performance because it excludes figures from newly opened and closed stores.