Tranche Update on ProAssurance Corporation's Equity Buyback Plan announced on February 24, 2011.

ProAssurance Corporation is a specialty insurer with expertise in healthcare professional liability, products liability for medical technology and life sciences, legal professional liability, and workers' compensation insurance. The Company's segments include Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance and Corporate. The Specialty Property and Casualty (Specialty P&C) segment is focused on professional liability insurance and medical technology liability insurance. Professional liability insurance is offered to healthcare providers and institutions and, to a lesser extent, to attorneys and their firms. The Workers' Compensation Insurance segment offers workers' compensation products in approximately 19 states in the East, South and Midwest regions of the continental United States. The Segregated Portfolio Cell Reinsurance segment includes the results of SPCs at Inova Re and Eastern Re, the Company's Cayman Islands SPC operations.