Thursday 30 March 2017

Former investment banker and Clongowes boy O'Callaghan (46, right) was a high-flying technology gazillionaire, building up Riverdeep and then Houghton Mifflin into one of the world's biggest online publishers before everything came unstock during the financial crisis.

Placeholder

Please sign in or register with Independent.ie to access the Rich List articles.

Sign In

Also in Business