International Securities Exchange ( ISE) shares were up more than 8% after it posted fourth-quarter profits of $15.1 million, or 38 cents a share, compared with $10 million, or 26 cents a share, a year ago. The exchange also reported that its average daily volume for equity and index options contracts jumped 17.3% year over year. Shares were gaining $3.45 to $46.15.

MGIC Investment ( MTG) and Radian Group ( RDN) both surged on word that the insurers will merge to form a new company called MGIC Radian Financial Group. MGIC shares were rising $6.88, or 10.9%, to $69.81. Radian shares were up $5.50, or 9%, to $66.34.

Security Capital Assurance ( SCA) jumped on better-than-expected fourth-quarter results. The insurer said it earned $37.1 million excluding items, or 58 cents a share, beating estimates by a penny. Shares were higher by $2.30, or 7.9%, to $31.32.

Infinity Property & Casualty ( IPCC) raised its quarterly dividend by 20% to 9 cents a share. Shares were climbing 50 cents, or 1%, to $49.21.

RenaissanceRe ( RNR) rose after the Securities and Exchange Commission accepted its $15 million settlement offer in regard to an investigation of company restatements for 2001 through 2003. Shares were up 52 cents, or 1%, to $54.72.

Allied Capital ( ALD) fell on word the lender was subpoenaed by the U.S. Attorney's Office for the District of Columbia over its use of private investigators in a battle with short sellers. An analyst with AG Edwards cut the firm's rating to hold from buy. Shares were slipping 41 cents, or 1.4%, to $29.16.

Thomas Weisel ( TWPG) dropped on news that the broker's chief financial officer, Robert West, will leave on April 2. Shares were losing 37 cents, or 1.9%, to $18.77.