According to Robert Lacey, his biographer, Lansky was worth no more than $5 - 6 million at his peak, and substantially less over his later years because the Justice Dept. kept hounding him, which limited his ability to operate his usual rackets. His legal fees in his unsuccessful appeal of Israel's denial of his citizenship request, and his successful defense of four felony charges against him when he returned to the US, drained his assets. According to Lacey, he blew his last $50 grand on an unsuccessful operation to correct a chronic neurological condition in his ne'er do well son, Buddy. After his death, his widow, Teddy, though he must have had a lot of money stashed away somewhere, but neither she, nor Vincent (Jimmy Blue Eyes) Alo were able to find it. As far as I know, his brother, Jake, was always loyal to him.