Big-box Retail companies shares down at 10 a.m.

Shares of some top big-box retail companies are down at 10 a.m.:

Costco Wholesale Corp. fell $1.18 or .8 percent, to $150.32.

Target fell $.52 or .6 percent, to $81.55.

Wal-Mart Stores Inc. fell $1.13 or 1.4 percent, to $81.12.