DALLAS--(BUSINESS WIRE)--National residential mortgage lender PrimeLending, a PlainsCapital Company, is celebrating its 40th anniversary. Since opening its doors in 1986, the company has helped individuals and families achieve their homeownership dreams by making one of life's biggest financial decisions simpler.Since opening its doors on July 8, 1986, PrimeLending has grown from a small Dallas-based mortgage lender into a nationally recognized company serving homebuyers and homeowners in all 50