The beauty supplies retailer will replace R.R. Donnelley & Sons, which will move into the S&P SmallCap 600 index. The print service company is expected to spin off certain operations and assets later this month.
Sally Beauty traded over 5 million shares, more than triple its 30-day moving average volume of 1.5 million shares, according to market data. The stock is currently on track for its best day since February 4, when it gained 13.1 percent.
The eligibility criteria for the S&P MidCap 400 level is $1.4 billion to $5.9 billion in market capitalization. For the S&P SmallCap 600, the level is $400 million to $1.8 billion.
--CNBC's Gina Francolla and Christopher Hayes contributed to this report.