It’s spring in real estate, so it is time for a quick primer on how to read the Multiple Listing Service (MLS) and alternate real estate listing sites.

What does UAG mean? What does RAC mean? Most of our clients “web around” to sites like Zillow and Realtor.com to look at images of properties for sale. We create customized searches with our database, but the raw data is out there for everyone now. This list will help you read the data and understand why some property disappears and sometimes reappears on the lists.

Here is the way it is supposed to work:

MLS properties for sale that buyers can see and make offers on:

ACT means active.

NEW means just listed. (These include properties that were listed before under a different MLS number.)

PCG means price change.

Properties marked BOM have come back on the market after the active marketing has been suspended by being UAG, WDN, CAN, or EXP.

RAC, which means reactivated.

MLS properties that buyers can see, but are already spoken for:

The general category for houses that are legally spoken for is pending. Some agents continue to show houses that are pending, just in case something goes wrong.

Properties that have CTG have an Offer accepted, but there are still contingencies. This may be a home inspection or a mortgage contingency.

Properties that have ACT with a little clock icon have an Offer accepted, but there are still contingencies with a specific deadline.

CTG, ACT with a clock, and UAG all have signed purchase contracts. Some have Offers to Purchase only and some have Purchase and Sales Agreements.

Properties that are no longer for sale, but are found on some MLS lists:

Properties that read UAG are under sales agreement and not actively being marketed. In most interfaces, they disappear from view.

Properties that have the designation CAN have a cancelled contract between the agent and the owner before the contract period ended. Those that read EXP had the listing contract expire. The seller may have chosen not to sell. Or may be selling now as a for-sale-by-owner. Or may list again with the same agent or different one. Look for the house again as a “for-sale-by-owner” or as BOM or RAC or NEW.

Properties that have WDN are withdrawn from the market. This could mean the seller needs a week off from showing it, or a month. However, the agent is still under contract with the seller. These may come back as BOM or RAC or NEW.

Properties that were never for sale:

Some of these sites have lists of properties designated as “pre-foreclosure.” Because of the way these lists are compiled, many of these house are not for sale and will not be for sale.

Our agents can check those out for you, but they rarely come onto the market without being listed by an agent. You are unlikely to be able to buy one before it is listed because the lending institution that owns the property is legally bound to get the highest possible price for it. That is best done by hiring a listing agent to market the property.