Every strategic planning meeting eventually wanders into the same swamp.
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Somebody says TAM. Somebody says SAM. Somebody says SOM. Everybody nods because the acronyms sound familiar. The board has seen them before. The management team has a slide. The sales team has a forecast. The product team has a roadmap. The finance team has a model.
And then, forty minutes later, everyone has agreed to a market-sizing chart that looks professional and quietly damages the next six months of decision-making.
Why?
Because nobody in the room is using the words the same way.
The most common version of this problem is actually worse than mixing up TAM, SAM, and SOM. It is when five people all say TAM and each of them means something different. To one person, TAM means the giant number that looks good in an investor deck. To another, TAM means the market the company can serve with the current product. To someone else, TAM means the sales forecast. To the board, sometimes, TAM is just a test of whether the company sounds ambitious enough.
This is not just a vocabulary problem. It is a management problem.
If your team does not define these terms consistently, you will make bad decisions about where to sell, what to build, which customers to support, and which markets to ignore. You will over-invest in markets you cannot reach, under-invest in markets you can dominate, and spend board meetings arguing about numbers instead of making decisions.
So let us make this simple.
TAM, SAM, and SOM are not three sizes of the same market. They are three different questions.
The Simple Version: I Am, I Will Be, I Might Be
SOM is "I am." This is the market you can actually win today. Not after three roadmap releases. Not after hiring a new regional sales team. Today. With the product you have, the proof data you have, the customer access you have, the support model you have, and the reputation you have.
SAM is "I will be." This is the field of customer spend you are committed to serving. It includes what an informed external observer would reasonably say is your accessible business domain, including the market you are building toward through your roadmap, proof data, support model, and commercial plan.
TAM is "I might be." This is the broader universe of customer spend you could theoretically pursue if you chose to expand your product, your business model, your roadmap, or your strategic ambition.
That is it. I am. I will be. I might be.
If you can get your management team and board to agree on those three sentences, you are already ahead of most companies.
SOM: The Market You Can Actually Win
Let us start at the bottom, because this is where reality lives.
SOM stands for Served Obtainable Market. The important word is not "market." The important word is "obtainable."
This is the customer spend you can actually get.
That means the customer has a real need, your product can meet the requirement, your team has access to the right people, your proof data is sufficient or credibly obtainable, your support model can handle the account, and you are not blocked by a channel, a geography, an incumbent relationship, or a technical requirement you simply cannot meet.
This is where many teams lie to themselves without intending to.
They say, "That customer is in our market." Fine. But can you sell to them?
If the customer has already decided it will only buy through a service provider, and you only sell equipment directly, that may not be obtainable today. If the key decision-maker is locked into an incumbent competitor, that is not a market-size problem. That is a SOM problem. If the customer needs a capability or requirement you do not have, and cannot fake, that is not in your SOM today.
And here is the subtle but important part: if your product technically works but performs poorly, that may still be in your SOM. You are just weak there. That is different from pretending the market is completely inaccessible.
A weak SOM position is something you can manage. You can improve performance, generate proof data, change the sales motion, build support, or target a narrower customer set. But calling something obtainable when it is not obtainable is how companies waste years, delude themselves into thinking they are more competitive than they actually are, and avoid fixing the gaps that would make the market genuinely obtainable.
SAM: The Market You Are Building For
SAM stands for Serviceable Addressable Market.
This is where the complex strategy conversation starts.
Your SAM is not your fantasy. It is not your sales forecast. It is not your current revenue. It is not just your installed base. It is the portion of the broader market that an informed external observer would reasonably say you are in, or are committed to being in.
A useful rule of thumb is this: your SAM is the total customer spend in your space, across won and lost business, that goes to you or to competitors solving the same business problem. It is not the sum of every bid, because multiple competitors may bid on the same deal. It is the sum of what customers actually buy from you, from direct competitors, from adjacent substitute technologies, from service providers, or from themselves if they build the capability internally.
That last point matters. "Build it yourself" is often a real competitor. If a customer chooses to buy from you instead of building the capability internally, the SAM did not change. Your SOM did.
The question is not, "Do the alternatives look exactly like our product?" The question is, "Are they competing for the same customer budget to solve the same business problem?"
This is especially important in deep tech, capital equipment, life sciences tools, advanced materials, semiconductors, climate hardware, and industrial systems. In those markets, the same customer problem can be solved through multiple architectures, service models, workflows, and purchasing paths. Your SAM should capture that competitive reality.
TAM: The Number Everyone Wants and Almost Nobody Uses Well
Now let us talk about TAM.
TAM stands for Total Addressable Market. It is the biggest number. It is also the easiest number to misuse.
Boards want it. Investors want it. Pitch decks need it. Everyone wants to know whether the opportunity is "big enough." That is understandable. Nobody wants to fund a company whose best possible outcome is too small to matter.
But TAM is rarely the number that should drive your operating decisions.
TAM is the broader universe of budget that could be relevant if you expanded your product, changed your roadmap, entered adjacent markets, or decided to compete in a larger problem space. It answers the question: what could we become if we chose to?
That is useful. But be honest: until you choose to fund that expansion, staff it, build it, sell it, and support it, the TAM is not your business. It is a nearby activity for someone else to monetize.
If you sell a specialized manufacturing tool, your TAM might include adjacent testing, inspection, metrology, automation, or workflow budgets. Great. Those categories belong in the TAM discussion. But they only become realistic SAM if you decide to do something about them.
TAM is the strategic option space. SAM is the market you are building for. SOM is the market you can win.
If those three collapse into one number, the slide may look cleaner, but the company becomes less strategic.
The Gap Is the Work
The most useful strategic conversation is usually not, "How big is the TAM?"
The useful conversation is, "Why is our SOM smaller than our SAM?"
That gap tells you what the company has to do. If the SAM is large but the SOM is small because you lack customer relationships, that is a sales and market-access problem. If you lack proof data, that is an applications and validation problem. If the product is missing a required capability, that is a roadmap problem. If the support model cannot handle customer volume, that is an operating model problem. If the customer does not believe you can execute at scale, that is a credibility problem.
Those are different problems. They require different actions.
This is why the SAM-to-SOM gap is so valuable. It turns market sizing from a slide into a management system.
The gap is not just a number. The gap is the work.
Now for the Part That Makes People Uncomfortable
Your SOM is not permanent.
It can shrink. It can decay. It can go to zero.
If customer requirements keep moving and your roadmap does not, your obtainable market gets smaller every year. You may still point to the same SAM. The SAM may even be growing. You may still tell the board the market is huge. You may still have old customers and old revenue.
But if the power requirements, throughput requirements, compliance requirements, automation requirements, or integration requirements move past your product, your SOM is quietly disappearing.
A company thinks it is defending an existing market. In reality, it may be harvesting the end of an old one.
That is why SOM has to be tied to roadmap. The market you can obtain is a function of the product and operating choices you make. If you build the right capabilities, your SOM can expand toward your SAM. If you do not, your SOM decays.
The Bottom Line
TAM, SAM, and SOM are not investor decoration. They are not interchangeable. And they are not useful unless they force decisions.
TAM is the world you might enter. SAM is the market you are building for. SOM is the market you can win.
The next time your team shows a market-sizing slide, do not start by asking whether the TAM is big enough. Ask whether everyone in the room is using the same definition. Ask what is truly obtainable today. Ask what is committed through the roadmap. Ask what is merely possible if the company chose to pursue it.
Most importantly, ask one question for every segment: what has to be true for more of the SAM to become SOM?
That is where the real strategy lives.
Market sizing is not about proving the company could be huge someday. It is about deciding what the company should do now.
Market Operandi helps deep tech companies turn market sizing from board-deck theater into real strategic decisions. If your team is arguing about TAM, SAM, and SOM instead of using them to make trade-off decisions, that is exactly the kind of working session worth having.
Listen to this blog here: https://on.soundcloud.com/dzxhvprE04IgrxNCNy
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Contact us at Market Operandi for a complimentary 20-minute consultation. We'll help you with the questions you need to ask in order to calculate your true TAM, SAM, and SOM.
Abhay Chakra Sadineni, Chief of Staff, Market Operandi
About the Author:
Abhay brings a multidisciplinary background across engineering, operations, biopharma strategy, and commercialization to the Chief of Staff role. He is currently pursuing an MBA and MEng in Bioengineering at UC Berkeley, where his work focuses on the intersection of deep tech, biotech, energy, AI, and venture strategy.
Before Berkeley, Abhay worked in aerospace design engineering at Cyient and later in emerging markets operations at Amazon, where he supported analytics and process improvement across high-growth regions while developing experience in market analysis and structured execution. He also worked as a biopharma consultant, supporting strategy across life sciences, healthcare markets, and commercialization planning. Alongside this work, he co-founded a deep tech venture focused on patented liquid adulteration detection technology and biomimicry-inspired sensing.
At Market Operandi, Abhay supports commercialization strategy, customer discovery, investor and client materials, operational follow-through, and structured execution for deep tech startups.