Everyone knows how complex the state and federal tax codes are. The Wall Street Journal warns speculators to avoid trading commodity Exchange Traded Funds (ETFs) and Exchange Traded Notes (ETNs) and those that own multilateral partnerships because the cost of preparing tax reports on those trades quite likely will exceed trading profits. (Paid sub required.) 

It's better to trade the stocks of companies that produce and process commodities and the stocks of multilateral partnerships than the ETFs and ETNs that own them.