When Macy's (M) - Get Report announced better-than-expected quarterly earnings on August 11 as well as plans to close approximately 100 underperforming store locations, its shares closed 17% higher from the previous day's close.

When Valeant Pharmaceuticals (VRX) announced on August 9 that it is "evaluating strategic alternatives" for a number of businesses with revenue greater than $2 billion to pay down debt, and that the company has received some unsolicited bids, shares advanced more than 25% on the news, despite an earnings miss. (The stock has given up some of its gains after news surfaced the next day that federal prosecutors would investigate Valeant's ties to specialist pharmacy Philidor.)

The average stock has gained just under 0.5% on its earnings reaction day, according to Bespoke Investment Group, but some stocks, such as Macy's and Valeant, have had added news and/or better-than-expected results (despite some stocks posting losses) that have contributed to double-digit share price gains on earnings day.

Which stocks had the highest gains following earnings? Bespoke, a Harrison, N.Y.-based investment firm, came up with a list of the 40 stocks that had the best performance on their earnings reaction days (defined as the first trading day following the report).

Here are the 10 stocks with the best performance so far, according to Bespoke.

Bespoke used only stocks trading over $5 a share. The list is of stocks that have reported earnings through Aug. 11.