First of all, Hong Kong's OCTB does not involve in commercial crime, but Commercial Crime Bureau (CCB) does.
OCTB's job, as its name - Organized Crime and Triad Bureau, is to take care serious organized crime. Unless it is serious enough to the level of Madoff's case, usually CCB will take care most of them.
In the U.S., there is no single departments or law enforcement agency to deal with commercial crimes. But the following agencies will participate:
1. U.S. Secret Service - Counterfeit currency
2. IRS - Tax fraud and evasion
3. SEC - Security crime
4. Attorney General / Deparment of Insurance of each state - insurance fraud
5. FBI - The rest.