BNP Residential Properties ( BNP) surged after the North Carolina-based REIT agreed to be acquired by Australia's Babcock & Brown for $316 million. Babcock & Brown will pay $24 a share for BNP, a 39% premium over Wednesday's closing price of $17.24. Babcock & Brown also will assume or refinance $450 million of the real estate investment trust's debt. The deal is expected to close in the fourth quarter. Shares climbed $6.41, or 37.18%, to $23.65. Aetna ( AET) lost ground after the Hartford, Conn.-based insurer was downgraded by Prudential Equity Group ( PRU) to neutral from overweight. Shares slipped 93 cents, or 2.45%, to $37.07. Assurant ( AIZ) gained after the New York-based insurer said it will sell its equity interest in Private Health Care Systems to MultiPlan, a New York health care financial-risk manager, for about $150 million. The sale is expected to close by the end of the year. Shares gained 61 cents, or 1.20%, to $51.50. SWS Group ( SWS) lost ground after the Dallas-based brokerage posted relatively flat fourth-quarter earnings. The company earned $5.4 million, or 30 cents a share, compared to earnings of $5.3 million, or 30 cents a share, in the year-ago period. Revenue rose to $100.6 million from $92.1 million. Shares dropped 99 cents, or 3.89%, to $24.46. BankFinancial ( BFIN) gained after the Burr Ridge, Ill.-based savings and loan said its board had authorized the repurchase of up to 2.4 million shares, which represents 10% of the company's outstanding stock. Shares gained 38 cents, or 2.23%, to $17.45. NGP Capital Resources ( NGPC) gained after Matrix Research initiated coverage of the Houston-based principal investment firm with a buy rating. Shares gained 45 cents, or 3.30%, to $14.10.