I will occasionally notice a listing that has been expired and then immediately relisted with a slightly different address (such as the letter A at the end or the street number or something similar). Is this permitted?

This is not permitted. When alerted to such a listing, MLS Staff will correct the address and, if it appears that an agent or broker has a pattern of this activity, the matter will be forwarded to the Grievance Committee for investigation, which could include the filing of a Professional Standards complaint based upon an alleged violation of Article 12 of the Code of Ethics. This practice is problematic as it negatively impacts the integrity of the MLS data and doesn’t present a true picture to the public and cooperating brokers with respect to the property address, history, and number of days on market. If you come across one of these listings, please use the “Report Violations/Errors” tool in the upper right hand corner of the page report to notify MLS Staff (your name will remain confidential).