Jingi (1991)

In a case of mistaken identity, a low-level gangster shoots an innocent man, thinking he's a rival crime boss. Realizing his mistake, he nurses the man to health. When he learns his victim is a former banker who lost his job and is disillusioned with "the system", they decide to partner up and get rich running a stock investment scam. The rival boss is still around, however, and the pair's sudden success attracts his attention.