Why SOM Matters More Than Theoretical Market Size
In previous discussions, we explored TAM (Total Addressable Market)—the total number of vehicles that could potentially need auto repair services—and SAM (Serviceable Available Market)—the portion of TAM that is realistically available to independent repair shops.
However, just because a vehicle is part of your SAM does not mean it will come to your shop.
This is where SOM (Serviceable Obtainable Market) comes in. SOM represents the actual market share your shop can expect to win based on competition, marketing effectiveness, customer retention, and service offerings.
Understanding SOM helps shop owners set realistic business expectations, monitor market shifts, optimize pricing strategies, and track business performance over time. While TAM and SAM are theoretical numbers, SOM is what determines your shop’s revenue and profitability.
How to Calculate SOM for Your Auto Repair Shop
SOM is a percentage of SAM that you can realistically capture based on competitive dynamics, brand strength, and marketing effectiveness.
Step 1: Start with Your SAM Number
Your SAM is the total number of service visits available to independent repair shops in your market. This number has already been filtered to exclude:
- Dealership-loyal customers
- Fleet vehicles with exclusive service contracts
- Competitor-loyal customers
- DIY vehicle owners
Example: If your SAM is 48,195 service visits per year, that means these are the customers theoretically available to you.
Step 2: Assess Your Competition
The next step is to analyze how much of SAM you can realistically capture by evaluating how many competing shops exist and how strong they are.
- If 10 shops serve the same market, an even split would give each shop 10% of the market.
- However, market share is rarely split evenly. Some shops dominate through strong branding, reputation, and marketing, while others struggle to maintain visibility.
Step 3: Adjust for Competitive Strengths and Weaknesses
Your shop’s ability to win SOM is determined by several key factors:
- Brand Strength & Reputation – A well-known, trusted shop with strong customer loyalty will capture a larger SOM.
- Marketing & Visibility – Shops that rank higher in Google search results, run ads, and have strong social proof will attract more customers.
- Unique Service Offerings – Shops specializing in fleet maintenance, hybrid repairs, or European vehicles may capture a larger share of a niche market.
- Customer Retention Rate – If customers return to your shop instead of shopping around, you’ll secure a more stable SOM.
Example SOM Calculation
Let’s say your SAM is 48,195 service visits per year, and there are 10 competing shops in the region.
- If the market were split evenly, each shop would get 4,819 visits per year (10%).
- However, if your shop is well-known, has strong online visibility, and retains customers well, you may win 20% instead of 10%.
Final SOM Estimate: 9,639 service visits per year
This number represents the real customer base your shop can expect to capture if business performance remains consistent.
How Your Services Impact SOM
Shops that offer specialized services often have a smaller SAM but a larger SOM. Specialization limits the number of potential customers, but it also reduces direct competition and increases pricing power.
- Fleet-Only Repair Shops – Instead of competing for general customers, fleet shops capture a more concentrated and consistent loyal segment.
- Brand Specialists – By focusing on a brand segment, or specific brand types (for example: BMW, Mercedes, and Audi owners), these shops serve a smaller market but may have higher repair order values as they would market as specialized talent.
- EV & Hybrid Repairs – A niche market with lower competition, but requires investment in tools and certification as well as specialized talent.
- Diesel Truck Repair – Targets a specific audience, but commands higher pricing and long-term customer relationships.
Smaller SOM does not mean lower profitability. Some of the most successful auto repair businesses operate in highly specialized markets where customers are more loyal and willing to pay premium pricing.
Why SOM is the Most Dynamic Market Metric
Unlike TAM and SAM, SOM shifts on a daily, weekly, and monthly basis.
Some factors that cause SOM to fluctuate in real time include:
- Daily booking trends – Sudden spikes in demand (bad weather, school starting, or pre-holiday travel) can temporarily increase SOM.
- Competitor promotions – A local shop running a deep discount on oil changes or brake jobs could reduce your SOM temporarily.
- Customer satisfaction & reviews – If your shop’s Google rating drops, fewer customers may choose you, shrinking SOM.
SOM must be continuously monitored to ensure business strategies are aligned with real-time market conditions.
How Competitive Shifts Impact SOM
SOM is the first place where competitive changes become visible. If your customer numbers drop, it could signal a competitor is becoming more aggressive or it may be that they are advancing in areas you are not aware of.
Key competitive factors that influence SOM:
- Google Ads & SEO – A competitor investing in paid search ads or ranking higher in Google Maps will redirect potential customers away from your shop.
- Service Offerings – If a competitor starts offering ADAS calibrations, EV repairs, or fleet contracts, they capture part of your market.
- Pricing & Promotions – If nearby shops start offering discounted services, loyalty programs, or extended warranties, they may pull customers from your business.
- Business Expansion – If a competitor opens a second location or hires aggressively, it signals a future attempt to capture more SOM.
Tracking competitor strategies is essential for maintaining and growing SOM. If competitors are outperforming you in marketing, service offerings, or pricing, adjustments may be necessary.
Tracking and Improving SOM Over Time
To ensure your shop is growing its SOM, consistently track:
- Projected vs. actual customer visits – Are you meeting your SOM expectations?
- Market penetration rate – Are you capturing a higher or lower percentage of available customers?
- Customer acquisition cost (CAC) – Is your marketing spend justified by the customers it brings in?
- Retention & repeat business metrics – Are customers coming back, or are they choosing competitors?
SOM is the foundation of a profitable and growing business. Monitoring it regularly ensures you can adjust marketing, pricing, and service offerings as needed.
Final Thoughts: Why SOM is the Most Actionable Market Metric
- TAM and SAM provide theoretical market potential, but SOM defines actual business success.
- SOM fluctuates constantly based on competitor actions, pricing, marketing, and customer loyalty.
- Tracking SOM over time helps diagnose growth opportunities and potential losses.
- Adjusting marketing strategies, pricing, and service offerings can help maintain or grow SOM.
While business owners can track some of this data manually, getting expert guidance from a marketing consultant or business coach ensures accuracy and helps refine strategic decisions. Accuracy in SOM tracking is key to preventing costly mistakes and maximizing profitability.
