The Pending Home Sales Index, a leading indicator of housing activity, measures housing contract activity, and is based on signed real estate contracts for existing single-family homes, condos and co-ops. When a seller accepts a sales contract on a property, it is recorded into a Multiple Listing Service (MLS) as a "pending home sale." The majority of pending home sales become home sale transactions, typically one to two months later. The National Association of Realtors collects pending home sales data from MLSs and large brokers. Altogether, data from over 100 MLSs & 60 large brokers is received providing a large sample size covering 50% of the existing home sales sample. This is equal to 20 percent of all transactions.