S&P MidCap 400 in Focus: RDN CECO

The S&P MidCap 400 is an index used to track mid-sized companies which have a market capitalization of $1.5 billion to $5.5 billion. According to S&P, midcap stocks make up roughly 7 percent of the U.S. equities market.

The index shed 9.88 points to 859.79.

Rumors are swirling that Merrill Lynch may issue a profit warning. The company declined to comment. Additionally, late Thursday, Moody's Investors Service cut ratings on MBIA Inc. and Ambac Financial Group Inc., two large bond insurers.

Meanwhile, light, sweet crude for July delivery rose $3.32 to $135.25 a barrel on the New York Mercantile Exchange.

Shares of Radian Group Inc. slipped 34 cents, or 13.1 percent, to $2.26. Earlier in the session, the mortgage insurer's stock touched an all-time low of $2.23. A UBS analyst cut his price target on the company Friday.

JetBlue Airways Corp. shares lost 35 cents, or 8.1 percent, to $3.95 as crude oil prices jumped on the Nymex.

Shares of AirTran Holdings Inc., which runs AirTran Airways, slipped 17 cents, or 6.2 percent, to $2.58.

On the gaining side, shares of Career Education Corp. added 87 cents, or 5.1 percent, to $18 after a Credit Suisse analyst upgraded fellow for-profit educator Apollo Group Inc.

Shares of CF Industries Holdings Inc., a fertilizer company, advanced $6.17, or 3.8 percent, to $168.32. On Friday, Merrill Lynch boosted its price target on the stock.

Shares of ITT Educational Services Inc. increased $3.81, or 4.5 percent, to $88.30. On Friday, analysts from Lehman Brothers and ThinkPanmure raised price targets on the company, and William Blair & Co. upgraded the stock.