Complex sentence: Blyth & Co. merged with Eastman Dillon Union Securities & Co. in 1972 and in 1979, Blyth, Eastman, Dillon & Co. merged with Paine Webber.
Split into simpler sentences: Blyth & Co. merged with Eastman Dillon Union Securities & Co. in 1972. In 1979, Blyth, Eastman, Dillon & Co. merged with Paine Webber.