Wilmington Trust Corp. yesterday announced it signed a definitive agreement to buy AST Capital Trust Co. for an undisclosed amount. The pending acquisition by Delaware-based Wilmington Trust, a leading provider of retirement services to individuals and institutions, would nearly double the amount of retirement plan assets and the number of plans it serves, to $41 billion and 3,000, respectively. AST Capital Trust will become part of Wilmington Trust's Corporate Client Services group.

   AST Capital Trust, with offices in Phoenix and Wilminton, provides trustee, trust administration and back-office services through financial advisors to retirement plans, high-net-worth clients and institutional investors.

   The deal is expected to close by the summer. Following a transition period, AST Capital Trust will assume the Wilmington Trust name. Wilmington Trust expects the deal to boost revenue by $27 million and be non-dilutive to earnings in 2008.