Large law firms have increasingly dabbled in the contingent-fee arena, representing corporate plaintiffs in large-scale matters, but there is one highly lucrative practice the firms can’t seem to make work.

When members of the disbanding Miller Alfano & Raspanti were looking for new homes last year, it was the qui tam practice created largely by Marc S. Raspanti that had the most trouble finding the right fit. And it wasn’t for a lack of interest from several big firms.