Two of the largest providers of anti-fraud software are about to merge. Sysdome, a maker of fraud prevention and decision-support tools, has agreed to be acquired by ISO. The transaction, which requires shareholder approval, is expected to close before the end of April. Earlier this year, ISO acquired AppIntelligence, a Weldon Spring, MO–based provider of Web-based analytic tools that, like Sysdome’s products, identify and detect fraud in the residential mortgage industry. …