Security Pacific sold a mortgage banking unit.

The subsidiary, Denver-based Security Pacific Mortgage, was sold to Fleet Financial Group, a bank holding company headquartered in Providence, R.I. Security Pacific acquired the unit in 1973 and will keep its commercial real estate portfolio while selling the residential mortgages to the Rhode Island company. Fleet said the purchase will increase its $14.5-billion mortgage servicing portfolio by $2.5 billion, making Fleet the nation’s third-largest mortgage banking company. Terms of the cash transaction, which is expected to be completed by Nov. 30, were not disclosed.