What Is The MLS?

It may sound strange to say I was sitting wondering “What is the MLS?” but there is a reason the real estate multiple listing service was at the forefront of my mind. I was at a business event called the Secret Knock and was lucky enough to meet, and spend time with, Ron Klien. Often called “The Grandfather of Possibilities” Ron Klien invented the magnetic strip on the back of credit cards and is the man who developed the Real Estate Multiple Listing Service system which is still at the heart of the MLS today. Having spoken with him at length, I realized that everything I thought I knew about the MLS was wrong.

What Is The MLS? There is no one MLS, but rather multiple local MLSs across the US. Each one is a local database built, managed, and funded by real estate professionals, to share property listings between member brokers. The public can visit MLS websites but must contact the listing broker for details and showings.

I imagined the MLS was one big website, but there are actually over 800 MLS’s in the US today, and the first MLS was created in the 1800s, so websites are a recent MLS development. I’ve put together this, a complete guide to the MLS where you’ll learn exactly what the MLS is, who has access, and how it can help or hinder you when buying or selling a home.

What Is The MLS?

I have already touched on the fact that the MLS is not actually “THE” MLS. Instead of it being one, cohesive website on which lists the majority of properties in the US “it” is actually a “them.”

“The” MLS is, in reality, approximately 800 separate websites. Each one is individually built,  maintained, and funded, by local Real Estate Associations to promote cooperation between agents, allowing them to provide a higher standard of service to their clients.

The National Association of Realtors® defines an MLS as:

“a private offer of cooperation and compensation by listing brokers to other real estate brokers.”

As a member of an MLS, a real estate agent can draw from a vast pool of potential properties for their buyers, as well as being able to share their sellers’ listings with a wide range of other agents and brokers.

While each MLS is a distinct, stand-alone entity, they are also, in many ways, interconnected. For every MLS:

  1. There is a single standard of data, called the real estate transaction standard, which is used by every MLS. The technical name for this is XML-based data feed. Standing for “Extensible Markup Language” XML is a specific computer language which allows a user to display online information, in the same format.
  2. Agents write the listing information in the same way for every property, but only a “snapshot” is available on the part of the MLS which can be viewed by the public.
  3. The comprehensive property listing is only available to member agents, who can be contacted by other members, and the public, through the MLS.
  4. In order to be covered by the National Association of Realtors® (NAR) Agents Liability Insurance, an MLS must follow the mandatory policies in the NAR  Handbook on Multiple Listing.

Oh, and just to throw a wrench in the works….

MLS isn’t owned or copyrighted by anyone in the US. It is a generic term so anyone can use it.  As a consequence, there are a number of other organizations using the name MLS, not all of whom afford the consumer the same level of protection.

To demonstrate this, I had a friend, who has never looked for homes online, to look for a suitable family home. We randomly chose Dayton, Ohio, and sat down to find a house.

This is what happened.

If you  Google, “Ohio MLS” your search results will take you to MLS.com where you will see a list of local real estate area that covers 44 separate metropolitan communities in the state. Also, there are four rural area options and links to foreclosures sorted by city. We drilled down through neighborhoods, and it was only at this point that we realized that Google had taken us to the foreclosure section of the website. We chose the “Find New Homes” tab and started again.

Do you know what?

That wasn’t right either.

This took us to new builds, so we clicked on the “about” page to look for hints, and at this point, we realized that this was not the MLS we were looking for. It was a company called “MLS.com” in Indiana that led back to another organization in Shanghai, China.

Did we ever find “The” MLS?

Yes, by searching “Buy a house in Dayton Ohio” and scrolling past all of the paid ad listings at the top, we finally found the Realtor.com website which hosts the National Association of Realtors MLS, which is, in turn, “fed” its information by the local Dayton Ohio real estate association.

The History Of “The” MLS

The Boards of Realtors® established the first “Real Estate Exchanges” which occurred on an appointed day each week. Members of a local Board of Realtors® would gather at their offices and “exchange” the information about the properties they had for sale. According to the NAR, this practice began in the 1800s.

And do you know what happened?

These nineteenth-century trailblazers would also come to meetings with plenty of cash, and many properties were essentially auctioned off on the spot to the highest bidder. These types of real estate exchange were common in the 1880s and 1890s and in 1907 the term “Multiple Listing Service” was first used.

By the 1920s local Multiple Listing Services could be found across the country and the regular meetings were no longer the only way to see the available properties. Instead, approximately once a  week, members would submit their listings to the office where staff would compile them into a book which was then sent out to all members for viewing. This way all members could see what was still for sale and available for showing, and which properties had been sold since the last edition.

But then the modern age arrived.

Once modems became a fixture in real estate brokerages, the books were replaced with a central computer to which agents could dial in, upload their client’s properties for sale and download the home specifications from other brokers.

The first internet appearance of the MLS came in 1996 when some property information began popping up on websites, but the info wasn’t “live” and did not necessarily reflect what was currently available. It did, however, allow buyers and their agents to see the types of home in their price range.
Since then each MLS has evolved so that each listing accurately reflects the status of a property, so those viewing the MLS know precisely what is still for sale and what has already been snapped up.

How Does An MLS Work?

When a real estate agent signs a contract with a homeowner, to sell their property, the agent will gather the applicable details such as the square footage, the number of living rooms, bedrooms, and washrooms, etc. and take preliminary photographs.

But there’s so much more to it.

The agent posts the listing to their local MLS, on their client’s behalf along with other documents such as client disclosures, Homeowner Association rules, zoning and permitting details. This additional documentation is viewable only by member agents and covers everything that a buyer might miss. For this reason, if you see something you like the look of on the local MLS website, you should always contact the listing agent.  There could be a wealth of background information available about your target property, some of which might rule it into or out of your search results.

Today, each MLS is updated every 15 minutes, so you can be as sure as it is possible to be that any “for sale” homes you see are actually still for sale.

What Are The Rules Of An MLS?

The National Association of Realtors® has developed the overarching guidelines for setting up, maintaining, and running an MLS in the US. The NAR update their MLS handbook each year, and they divide the policies it contains into four classifications:

  • M—Mandatory
  • R—Recommended
  • O—Optional
  • I—Informational

If they want to be covered under the National Association “master professional liability insurance policy,” a local branch of the National Association of Realtors® must include the mandatory policies in their own bylaws and/or policy handbook.

This practice ensures that each local MLS maintains particular standards of practice and a standardized format for their listings. However, with the recommended and optional elements of the policy, the local branches can still maintain a certain degree of autonomy and individuality.

Who Can Access An MLS?

Both the public and the member real estate agents can access the MLS database, but the information they see is different. The broker members of the MLS pay for access and maintenance, but they allow the public to view some data, as it is to the real estate agents advantage to have as many pairs of eyes on their available properties as possible.

I hooked in the same inexperienced friend as before and set them loose on the “Dayton, Oh real estate and homes for sale” page on Realtor.com.

The public MLS experience

Click on the price filter, and you have the option of filtering by house price, or by typing in your downpayment and maximum monthly payment. We chose a downpayment of $10,000 and a monthly payment of $1,000 which gave us a maximum purchase price of $145,780 which we set as our maximum.

We then set ou filters to:

  • Bedrooms – 3+
  • Bath – 2+
  • Property Type – House
  • Listings – Any
  • More filters – none set.

This gave us 410 properties to browse with the newest listings at the top, followed by “pending sales,” then the remaining homes.

Choosing a home at random the details available are:

Property Details:

“Spacious ranch home with a full semi-finished basement. The front bay windows grant so much natural light to the common living areas on the main floor. Large kitchen with a lot of cabinets and counter space with a formal dining area. Bar area in the kitchen the opens to a dining room with a large stone fireplace. Open comfortable design that makes the sqft of the property show. The main bathroom has neutral ceramic tile on the floor and walls and has a separate standing shower and bathtub. The master has two large closets to accommodate all your storage needs. Corner lot with a fenced rear yard.

School District: Dayton City SD”

Property taxes, sales history, neighborhood schools, and median listing price & price per square foot were also on display.

You are given the option of both contacting the agent for viewing and asking questions, as well as applying for preapproval on a mortgage, and there are 15 photographs of the interior.

The Brokers MLS Experience

While the public listing can give you an idea of how suitable the home might be for you, brokers have access to much more detailed information than the public. A real estate agent or broker can read sellers declarations, will know if the seller is open to offers, in a rush to sell to avoid foreclosure or has other specific issues that might impact a sale.

Zoning information, permit applications, impending neighborhood developments, all of the detailed background information, is at a member brokers fingertips. While you may be able to discover some of this info yourself, it would take a great deal of time and effort.

Is the MLS Free to Use?

The public access to MLS is free, but as I have discussed limited. Real estate agents and brokers pay a significant amount of money, in the hundreds of dollars, every year in order to have access to the databases.

On top of that, only members of the National Association of Realtors may us the MLS hosted on Realtor.com so brokers who use it must also pay membership dues to their local, state, and national Realtor associations.

It is estimated that the average real estate agent, in 2019, may pay in access of $1,000 dollars a year in order to have their listings included on Realtor.com and to have access to the data on other brokers properties.

How Accurate Are MLS Listings?

Local MLS Internet Data Exchange (IDX) feeds are generally considered to be the most accurate and up to date available.

In order to ensure that all listings are completed as fully and accurately as possible, members of a local MLS are fined if they do not enter the full details of a listing within 48 hours of signing the listing contract with a client. In some cases, it is within 24 hours.

Each local association may have slightly different minimum data requirements, such as the number of photographs that must be submitted. But the basics such as square footage, number of bedrooms, etc., these pieces of information will always be included.

Are All Homes That Are For Sale On MLS?

In a word…


By browsing Realtor.com, you will not see all of the local homes that are currently available for sale. For example, some homeowners choose to sell their property without the aid of a real estate agent. Members of the public are not regulated by the National Association of Realtors and as such the NAR cannot exert any control over the quality, and more importantly the accuracy of the information in a listing. So you will not see any “For Sale By Owner” properties on the MLS.

In addition, there are some areas of the country where other databases are available. These are hosted by:

  • Brokers and agents who are not members of the National Association of Realtors and have banded together to host their own MLS.
  • Large real estate brokerages who maintain an MLS exclusively for their own brokers and real estate agents.

For this reason, you should take the time to look further afield than Realtor.com when you are hunting for your next home.

Finally, “pocket listings” are not available for viewing on MLSs.

What Is A “Pocket Listing?”

From time to time a high-profile homeowner will place their property on the market. For some, having their home publicly displayed online would be a security risk. Others might not want the publicity that might surround the sale of their home and most celebrity sellers would want to avoid an onslaught of fake buyers who sign up for viewings to be nosey.

These properties, which are kept out of the MLS database are often referred to as pocket listings. The name arose because the agent would be said to be keeping the listing “hidden in their back pocket.”

In these cases, only prescreened, prequalified buyers with whom the agent is working will be aware of the property’s “For Sale” status.

Can You List Your “For Sale By Owner” House On The MLS?

No, but Yes.

I have already touched on the fact that individuals are not permitted to post their listings on Realtor.com and the same rules apply to the MLSs type databases hosted by brokerages and local non-NAR real estate associations.


There are two ways in which you can sneak your listing on there if you want to.

A Flat Fee MLS Listing

Some brokerages provide what they call a “Flat fee MLS listing.” This service allows a homeowner to list their property and contact details, but nothing else. There is no facility to upload additional information, interact with brokers etc. AND you still have to commit to paying the buyers real estate agent or broker, a commission. The commission you are willing to pay must be included in the listing so that buyers agents can decide whether or not they want to work on the transaction.

Get Your Own Real Estate License

If this is the first of many properties you plan to buy and sell, it might be worthwhile studying for and taking your state real estate licensing exams. Once you pass you must sign up with a brokerage before you can practice. Be sure to apply to brokers who are members of the NAR as only real estate agents who are part of a member brokerage can join the NAR. Now, as long as you pay your membership fees, you can list as an actual agent.

What Are The Benefits Of An MLS?

In the absence of an MLS, you might imagine that in today’s internet age it would still be relatively simple to buy a home online. After all, what more would you need to do other than hit up one site, right?


Because even the other big house hunting sites such as Zillow.com, obtain the majority of their listings from MLS.

So let’s imagine a world, without MLS.

  1. Without an MLS house hunters would have to:
  • Search multiple real estate agents websites for property listings but before you could do that you would need to research the real estate agents operating in the area in which you were looking.
  • Monitor other sites such as Craigslist.
  • Hunt down those old fashioned things they call magazines and newspapers in the local area.
  • Tour the target neighborhood for homes with “For Sale” signs in their yard.

And then, guess what?

Once you had all of those listings from disparate sources, you would have to contend with the differences in the format of the listings.

2. Some might focus on the square footage of the home and the lot, while others might not mention this information at all. The same goes for every specification such as bedrooms, washrooms etc. The standard format of MLS ensures that you are more easily able to compare homes and have a complete picture of the property.

Which brings us onto honesty.

3. Most of us have made or heard jokes about the ways real estate agents might describe a home that is falling apart as a  “fixer upper” or “handyman special.” In fact, I have even seen one listing boasting of the “quiet, low traffic neighborhood” which turned out to be next door to a cemetery.

At best, if there was no MLS, there would be a lot more “creativity” in listings and at worst there would be excessive dishonesty.

4. Sellers would have less exposure. The benefits of MLS are not restricted to buyers. For sellers and their agents, the MLS provides a platform which allows them to place their listing in front of anyone who is house hunting in the area. By reaching more potential buyers, MLS provides a greater opportunity to sell more quickly.

  1. The MLS hosted by the NAR is updated every 15 minutes, allowing you to see, at a glance, those homes which are under offer/pending, sold, or still available. It also enables you to see properties which have been placed for sale less than a half hour beforehand. Without the MLS you might go chasing homes which had already sold or miss out on houses that have just been placed on the market.

But, nothing is perfect, and there are some negatives to the system.

What Are The Downsides Of An MLS?

When Realtor.com was the primary internet destination for house hunters, the only downside was, really, that not every house for sale was listed. However, as other sites have emerged, so to have other disadvantages.

  1. The NAR MLS excludes real estate agents and brokers who are not members of their local real estate associations. As a consequence, although you will see more, high quality, and up to date listings here than anywhere else, it is not comprehensive.
  2. There is also the issue of innovation. Members of the NAR and Realtor.com have had the lion’s share of the market for a considerable period. When this happens, it can become less important to evolve and stay on top of current and emerging trends. So there is a chance that the MLS will become a dinosaur, while sites such as Trulia and Zillow race grow and develop new ways of interacting with buyers, sellers, and their agents. So, for example, while Realtor.com lists the local schools, Trulia has local school reviews as well as other resources such as local crime statistics, and a “find an agent” feature.
  3. Finally, for agents, there is another issue. Having a home listed online makes it especially hard to work out which agent should be compensated as the one who bought the buyer to the table. Should it be the listing agent because their ad caught the buyers eye or the buyer’s agent who made contact with the seller’s team and arranged the viewing?

The Future Of The MLS

So, what does the future hold for the MLS?

With over 720,000 members the National Association of Realtors is the most significant trade association in the US. However, the Association of Real Estate License Law Officials estimate that there are approximately 2 million active real estate licenses in the US, and even accounting for those agents who are not currently practicing, there are a significant number of real estate agents working outside of the NAR.

With the creation of competing websites, Realtor.com is no longer the only option for an agent who seeks online visibility for their properties, and some of these alternatives are doing much more than the MLS.
To maintain their “top dog” status, the MLS system will have to reform and continue to evolve. Some of the suggested improvements include:

  1. Amalgamating all of the local MLSs into one, national MLS which would have a single format and data standard.
  2. The creation of social media tools that would enable the easy sharing of property listings from within MLS.
  3. Building a second MLS for the public which would have the same kind of tools as Zillow, Redfin, and other competitors.
  4. Streamlining the internal administrative costs and processes in order to make the system cheaper to run.
  5. Giving non-NAR members the opportunity to list and access the database, perhaps at a higher, non-members subscription rate.

There is probably much more the MLS could do in order to stay relevant. I just hope that it is able to move with the times and continue to provide the service that it created in the first place.




Geoff Southworth is the creator of RealEstateInfoGuide.com, the site that helps new homeowners, investors, and homeowners-to-be successfully navigate the complex world of property ownership. Geoff is a real estate investor of 8 years has had experience as a manager of a debt-free, private real estate equity fund, as well as a Registered Nurse in Emergency Trauma and Cardiac Cath Lab Care. As a result, he has developed a unique “people first, business second” approach to real estate.

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