I called the GLOBEX control center, and the analyst was very helpful. Here is why a "bull put spread" or a "bear call spread" wasn't acknowledged by Globex: CME globex is in the process of eliminating Exchange-Defined Options Strategies (EDS). CME Group currently prelists approximately 360,000 option spreads per week, known as EDS. Less than 1% of the more than 360,000 EDS have activity. Because of customer and system provider demand, CME Group has chosen to remove all EDS and make all option strategies user defined. A User-Defined Spread (UDS) is an option spread that a trader creates by defining the spread's legs and ratios. CME Globex receives these legs and creates a tradable instrument that is disseminated to the entire market. IF THE CREATED SPREAD MATCHES A KNOWN CMEG SPREAD TYPE (e.g., straddle), CME globex will properly identify the spread as that type. For a list of all CME Group recognized spreads, see the Electronic Trading Concepts document at www.cmegroup.com. This process will be completed by August 2, 2009. In order for me to create the bull put spread in IB TWS, I had to go to the Combo screen, and click generic, and fill in the parameters. When the spread is created, it is identified as a bull spread. The bid/ask of the spread are negative numbers because it is a credit spread, per IB. So, one has to buy the spread to receive the credit. Interestingly, the bull spread is NOT a recognized spread; neither is its sister, the bear call spread. In order to create a bull put spread, I have to go to the Combo screen and create a vertical spread. This is one of the recognized spreads..there are many, some I haven't heard of. When the spread is created, the bid/ask is positive, and one has to sell the spread in order to receive the credit.