Wal-Mart's gain of 6.4 percent gain in comparable store sales "added 2.4 percentage points to industry gain," the report said.

Comparable store sales, measuring sales at stores that have been in the same location for more than a year, jumped 4.3 percent in June compared with a year ago. The industry minus Wal-Mart gained 1.9 percent, the report said.

Wal-Mart said it found sales strong in grocery, entertainment and health and wellness products, ICSC reported.

Minus fuel sales from Sam's, Wal-mart's gain was 5.8 percent, the report said.

"Consistently warmer weather, stimulus checks, advertising and robust sales related the the July Fourth holiday," helped bump sales, Family Dollar Stores' Chief Executive Officer Howard Levine said in the ICSC statement.