S&P MidCap 400 in Focus: RDN MOD

The index declined 10.19 points, or 1.3 percent, to 808.38 in afternoon trading.

Radian's stock declined 30 cents, or 20.7 percent, to $1.15, after hitting $1.12 earlier in the session, which is an all-time low.

Shares of Avis Budget Group Inc. declined $1.12, or 13.4 percent, to $7.24, after rival Dollar Thrifty Automotive Inc. warned of a 2008 profit miss.

An analyst downgraded shares of publisher Lee Enterprises Inc., and the stock declined 52 cents, or 13 percent, to $3.47, after setting an all-time low of $3.45 earlier in the session.

On the rising side, shares of Modine Manufacturing Co. gained 92 cents, or 7.4 percent, to $13.29, following an analyst upgrade.

Shares of Flir Systems Inc., which makes thermal imaging and stabilized camera systems, rose $2.26, or 5.6 percent, to $42.84. A division of the company received a $49.8 million contract from the Navy.

Shares of ResMed Inc., which makes respiratory medical devices, advanced $1.84, or 5.2 percent, to $37.59.