"A CPO is an individual or organization which operates or solicits funds for a commodity pool; that is, an enterprise in which funds contributed by a number of persons are combined for the purpose of trading futures contracts or commodity options, or to invest in another commodity pool." National Futures Association (NFA) definition. The NFA regulates every firm or individual who conducts futures trading business with public customers.
A CPO will generally consist of an entity that accepts funds, securities or property for the purpose of trading commodity futures contracts. The CPO may also make its own trading decisions or more usually it will engage a commodity trading advisor (CTA) to do so on its behalf.
CPOs and CTAs are regulated by US federal government through the Commodity Futures Trading Commission (CFTC) with additional oversight from the National Futures Association (NFA).