A second former top executive at Berkshire Hathaway Inc.’s General Re insurance unit pleaded guilty Friday to conspiring to file false financial reports as part of a phony transaction designed to burnish the books at American International Group Inc., his company’s top customer.

Richard Napier, 53, a senior vice president at Gen Re in 2000 and 2001 when the sham transaction occurred, pleaded guilty Friday to a single criminal conspiracy count at U.S. District Court.