Alleghany rose the most since December as Reuters reported that the company was approached about the possible sale of its Transatlantic reinsurance unit.

PartnerRe said it would engage in discussions with hostile bidder Exor to seek a better offer than the $6.8 billion proposal that the target company called unacceptable.

The IRSs scrutiny of tax avoidance in offshore locations has discouraged bidders from taking over reinsurers.

XL Group, the insurer that acquired Catlin, named Citigroup veteran Eugene McQuade as chairman as the company prepares for increased regulatory scrutiny.

Exor upped the ante in the takeover battle for PartnerRe, raising its bid by 5.8% in a final push to beat out rival Axis for control of the reinsurer.

Allstate said its raising rates for drivers after profitability declined at its namesake auto unit.

Geico will charge drivers more after margins worsened.

Allstate said first-quarter profit rose 13% as margins improved at the property-liability business and catastrophe losses fell.