Buy & Cell(1989)

Herbie Altman is framed for Stock fraud by his boss when the SEC starts investigating his company. Sent to prison, he helps a fellow inmate successfully invest his money. Soon all the inmates want his help. To manage all the money, he forms CON INC. and runs it from the prison under the noses of the warden and the guards. But when the IRS and SEC begin to investigate this successful company, it looks like he may be in trouble again