NEW YORK (Standard & Poor's CreditWire) Oct. 21, 1999--Standard & Poor's today affirmed its ratings on Markel Corporation Group and related entities (see list below). At the same time, Standard & Poor's revised its CreditWatch implications on Terra Nova and its related entities (see list below) from developing to positive. The actions follow a completed review of the financial and operational impact of Markel's decision to purchase Terra Nova (Bermuda) Holdings Ltd.., a specialty property, casualty, marine and aviation insurance and reinsurance holding company for roughly $905 million and the assumption of $175 million of Terra Nova Debt. The outlook on Markel is negative. The negative outlook reflects Standard & Poor's belief that management's appetite for acquisition risk has increased.