Just a year after Stephen Holst joined McCann FitzGerald, the leading Irish law firm, a sudden jolt of fear rippled through the building.  The recent UCD graduate was still a trainee, seated near Hilary Marren, a partner who had begun her career during the collapse of Tony Ryan’s GPA. Marren was Holst’s boss at the time and not someone easily unsettled.  Yet now televisions were being switched on around the office as the news broke. The Dow Jones was plunging. One of America’s largest investment banks, Lehman Brothers, was collapsing. McCann FitzGerald had deep ties to London and New York,…