A.M. Best Co. has placed the financial strength rating (FSR) of A- (Excellent) and issuer credit rating (ICR) of “a-” of Vanliner Insurance Company (Vanliner) (Fenton, MO) under review with positive implications following the recent announcement by National Interstate Corporation (Richfield, OH) [NASDAQ:NATL] that its principal insurance subsidiary, National Interstate Insurance Company (NIIC), has executed a definitive agreement to acquire the parent of Vanliner, Vanliner Group, Inc., from UniGroup, Inc. Subsequent to the planned acquisition, Vanliner is expected to be reinsured by NIIC, which is the lead member of National Interstate Group. The transaction is expected to close by the end of second quarter 2010 pending customary closing conditions and regulatory approvals. Vanliner’s ratings will remain under review until the transaction has closed. Vanliner is primarily a provider of insurance solutions to the moving and storage industry, which compliments National Interstate Corporation’s niche orientation and focus on the transportation industry. The FSR of A (Excellent) and ICRs of “a+” of National Interstate Group and its members are unchanged by this transaction. For Best’s Credit Ratings, an overview of the rating process and rating methodologies, please visit www.ambest.com/ratings. The principal methodologies used in determining these ratings, including any additional methodologies and factors that may have been considered, can be found at www.ambest.com/ratings/methodology. Founded in 1899, A.M. Best Company is a global full-service credit rating organization dedicated to serving the financial and health care service industries, including insurance companies, banks, hospitals and health care system providers. For more information, visit www.ambest.com.