Morgan Stanley has succeeded in its bid to force an Irish stockbroker to stand as a co-defendant alongside the US bank in a case brought by a group of investors, including hundreds of nuns, which kicked off on Friday.

As first reported by Financial News in August, Morgan Stanley is being sued by a group of Irish investors, including the nuns, for allegedly failing to fulfil its contractual obligations related to €6bn of notes which resulted in the near total eradication of their investment.