A popular check fraud is for the offender to impersonate someone else in order to dupe an individual or firm into issuing a check to the impostor. The impostor then forges the payee's endorsement on the check and absconds with the funds or becomes insolvent, leaving innocent parties to allocate the loss among themselves. For most of the last half century, such fraud was governed by Section 3-405 of the UCC. The code section, along with the rest of UCC Articles 3 and 4, has recently undergone a major revision (1990). This revision of the impostor rule will increase the risk of loss to businesses and consumers that use checking accounts. This article first provides some background on the legal nature of a checking account. It then explains the basic operation of the impostor rule under the UCC with respect to forgery loss allocation. The article then discusses the changes to the impostor rule that the Revised Uniform Commercial Code will produce and how they likely will impact loss allocation among innocent parties. Finally, it considers some problematic aspects of the new impostor rule. 62 notes