Sales at major U.S. chain stores rose 2.6 percent in the week ended Aug. 2 compared with the same week a year ago after rising 2.2 percent the previous week, Instinet Research said in its weekly Redbook report, said.

Sales gained 0.9 percent compared with the previous month.

Sales tax holidays in some states contrinbuted to the highten activity.

"Retailers claim competition to be even more intense than usual possibly due to the child tax credit checks heading to 25 million taxpayers," Redbook said.