Huntsman Corp. (HUN, news, chart) is seeing double normal trading volume after a strategist appears to have opened a substantial collar spread. Shortly after 13:00 Eastern time, 18,750 of the HUN September 15 calls traded on the bid, or for $1.65 a contract. Meanwhile, the same number of September 10 puts traded offerside or for 85 cents a contract. A block of 1.3 million shares of HUN traded for $13.55 per shares at precisely the same time, which leads to the conclusion that the options trades were part of a collar spread. If so, the strategist is taking ownership of the shares, selling calls, and buying puts. The collar has the same risk profile as a bull call spread, but requires a much bigger capital outlay. The idea might be to hold HUN shares for the longer-term, but also hold some short-term protection in the form of September put options. The upside is also limited, however, due to the short calls with the 15 strike price.