S3 Sues Ion Group Affiliate Over Unpaid Capital Call (1)

An affiliate of Ion Group, the Irish financial software behemoth whose derivatives trading arm was hacked this year, was sued by a partner for allegedly backing out of an investment agreement.

S3 Partners LLC, a provider of short-interest, holdings and securities finance data, alleges that Ion-owned Fidessa Corp. owes the company $6.25 million but is refusing to pay because Fidessa and Ion have so much debt that it “simply cannot find the money,” according to a complaint filed Thursday in state court in Manhattan.

“While Fidessa portrays itself as a highly successful business, the truth appears to be ...