Interested Parties Information. This 9-digit number is used to uniquely identify a songwriter or publisher. IPI numbers are also referred to as CAE (Composer, Author and Publisher) numbers. The IPI database replaced the CAE database as the industry standard in 2001, but the two are often used interchangeably. Rights holders are assigned IPI numbers when they are granted membership to a PRO. You can find the IPI of an affiliated songwriter or publisher by performing a repertory search at ASCAP or BMI. Your IPI number is not the same as your ASCAP member ID or BMI account number.