The answer is money. The Patent Cooperation Treaty (PCT) is an international treaty with more than 150 Contracting States.Filing a US application first can preserve cash flow, especially if you are not sure about seeking international patent protection. The cost is inexpensive compared to the cost to prepare and file a U.S. patent application. Plus, no examination of the patent application takes place. The cost is inexpensive compared to the cost to prepare and file a U.S. patent application. Plus, no examination of the patent application takes place. If you would like further information on assignments, please let us know. INID codes are defined under WIPO Standard ST.9. Below is a list of codes that correspond to data on the U.S. patent at right.