Specifically, would there be any downside for an OPEC member to buy massive amounts of contracts to support prices on front month? Worst case, they take delivery on the oil and store it. In the meanwhile, spot prices for the entire market are levitated. I did some math, and assuming (hopefully correctly) the largest ultra large tankers carry 2.5m barrels, that is equivilent to 2500 CL contracts. Bought or sold at the right time, a tanker or three a day can manipulate the price of oil to the whims and desires of whoever does the manipulating. Total volume of CL front month has been averaging about 10-12k lately. In other words, 5 ULCC tankers trade hands TOTAL every day on NYMEX front month. Quite small # actually. Please debunk my theory with expertise of over the counter transactions that ignore possible nymex price manipulation.