Wal-Mart's (WMT) Q2 comparable store sales growth slipped into negative territory at -0.2% after analysts forecast a 0% to 2% range. In the U.S., the drop was -1.3%.
Walmart International sales rose 2.9% to $33B.
Sams Club revenue increased 2.6% to $14.53B on a comp store sales increase of 1.7%.
The company sets its outlook for FY13 EPS at $5.10 - $5.30, down from prior guidance of $5.20 - $5.40.
WMT -2.9% premarket.