Direct Answer: In lower middle market SaaS M&A in 2026, net revenue retention (NRR) has become a more decisive valuation driver than the Rule of 40 for most buyers. A company with NRR above 110% and a Rule of 40 score of 35 will typically command a higher multiple than a company with NRR of 90% and a Rule of 40 score of 45. Buyers are underwriting the compounding power of existing revenue before they underwrite growth efficiency. Both metrics matter — but they are not weighted equally in the current market.
Understanding the Two Metrics
The Rule of 40
The Rule of 40 is a composite metric calculated by adding a company’s annual revenue growth rate to its EBITDA margin. A score above 40 is the conventional threshold for a healthy SaaS business.
Formula: Rule of 40 = Revenue Growth Rate (%) + EBITDA Margin (%)
Example: A company growing at 25% with a 20% EBITDA margin scores 45.
The Rule of 40 was designed to capture the trade-off between growth and profitability in a single number — to allow comparison between high-growth, low-margin businesses and slower-growth, high-margin businesses using a single benchmark.
Net Revenue Retention
Net Revenue Retention measures how much revenue you retain from your existing customer base over a twelve-month period, including the effect of expansions, contractions, and churn.
Formula: NRR = (Starting ARR + Expansion ARR – Contraction ARR – Churned ARR) ÷ Starting ARR × 100
Example: A company starting the year with $10M ARR that adds $1.5M in expansions, loses $300K to contractions, and loses $200K to churn has NRR of 110%.
NRR above 100% means the existing customer base is growing in value without any new customer acquisition. It is a measure of the compounding power embedded in your current revenue base.
The Benchmark Tables Buyers Use
NRR Benchmarks and Their Valuation Impact
| NRR Range | Buyer Interpretation | Typical Valuation Impact |
|---|---|---|
| Below 85% | Significant churn problem; revenue not durable | Material discount to market multiple |
| 85–95% | Elevated churn; growth heavily dependent on new logos | Moderate discount; buyers will model worst-case churn |
| 95–105% | Stable retention; acceptable for most buyers | At or near median market multiple |
| 105–115% | Strong expansion dynamics; revenue compounds without new sales | Premium multiple; buyers underwrite expansion as a growth driver |
| Above 115% | Best-in-class; rare in LMM | Top-quartile multiple; competitive buyer interest |
Rule of 40 Benchmarks and Their Valuation Impact
| Rule of 40 Score | Composition | Buyer Interpretation | Valuation Impact |
|---|---|---|---|
| Below 20 | Any combination | Burning capital without sufficient growth or profitability | Significant discount; often requires explanation |
| 20–35 | Growth-heavy | Early stage growth investment; acceptable with strong NRR | Below median without strong offsetting metrics |
| 35–45 | Balanced | Healthy business; standard for LMM | Near median multiple |
| 45–55 | Balanced or margin-heavy | Strong capital efficiency | Above median multiple |
| Above 55 | Either component | Exceptional; self-funding growth | Premium multiple; competitive interest |
ARR Band vs. EV/ARR Multiple Reference Table (LMM, 2026)
| ARR Range | Median EV/ARR | Top Quartile EV/ARR | Key Differentiator |
|---|---|---|---|
| $3M–$5M | 2.5x–3.5x | 4.5x–5.5x | NRR and growth trajectory |
| $5M–$10M | 3.5x–4.5x | 5.5x–7x | NRR, Rule of 40, customer concentration |
| $10M–$20M | 4x–5.5x | 7x–9x | NRR, growth rate, management team independence |
| $20M–$30M | 5x–6.5x | 8x–11x | All metrics plus competitive process quality |
| $30M–$75M | 6x–8x | 10x–14x | Combination of all factors plus buyer competition |
Source: THA transaction experience, Aventis Advisors, SaaS Capital Index 2026
Why NRR Has Become the More Decisive Metric
In the 2020–2021 environment, growth rate was the dominant factor in SaaS valuations. Capital was cheap, buyers were aggressive, and high growth rates justified almost any multiple regardless of the underlying unit economics or retention profile.
The market has reset. The cost of capital has increased significantly, buyers are more disciplined, and the question has shifted from “how fast is this growing?” to “how durable is this revenue?”
NRR answers the durability question more directly than the Rule of 40 for three reasons.
NRR is a leading indicator. A company with 115% NRR will be larger in twelve months even if new customer acquisition stops completely. The growth is already embedded in the existing customer base. Buyers pay for embedded future value.
The Rule of 40 can be manipulated. A company can improve its Rule of 40 score by cutting costs without improving the underlying business. Reducing headcount, deferring marketing spend, or eliminating R&D investment can boost the EBITDA component without creating any additional value for a buyer. NRR is harder to engineer artificially over a sustained period.
NRR reveals product-market fit. Customers who expand their spend year over year are doing so because the product is delivering increasing value. This is the clearest available signal that the product is genuinely embedded in their operations and not at churn risk. A high Rule of 40 score does not tell a buyer anything about whether customers want to keep using the product.
When the Rule of 40 Matters More
NRR is not always the dominant metric. There are specific circumstances where the Rule of 40 carries more weight in the buyer’s valuation model.
PE buyer scenarios: Private equity buyers building a platform through add-on acquisitions are particularly focused on EBITDA and the Rule of 40 because their return model depends on EBITDA-based exit multiples. A company with strong NRR but no profitability may require capital investment to reach an EBITDA level that supports the platform exit thesis, which affects how the PE buyer underwrites the acquisition price.
Higher ARR bands: As companies scale above $20M in ARR, buyers begin to expect both strong NRR and strong Rule of 40 scores rather than viewing them as trade-offs. At this scale, NRR above 110% is expected, and the Rule of 40 becomes a differentiating factor among companies that all clear the NRR threshold.
Capital efficiency narratives: In the current market, a Rule of 40 score above 50 driven by genuine operational efficiency — not cost-cutting — signals a business that can scale profitably. This is a meaningful premium driver, particularly for strategic buyers who are evaluating the integration cost of bringing a capital-intensive business into their organization.
Positioning Both Metrics Before Going to Market
Understanding which metric will drive your valuation is only useful if you have time to improve it before initiating a process. For most founders, that window is twelve to eighteen months.
If your NRR is below 100%: The highest-leverage intervention before a sale is identifying and addressing the root causes of churn and contraction. This typically means investing in customer success, improving onboarding for new customers, addressing product gaps that lead to downgrades, and structuring pricing to incentivize expansion rather than contraction.
Improving NRR from 93% to 108% over eighteen months does more for your valuation than almost any other single operational change, because the multiple improvement compounds with the ARR improvement to produce a significantly higher enterprise value.
If your Rule of 40 score is below 35: The path to improvement depends on the composition of the gap. If you are growing fast but burning capital, the focus is on improving unit economics — CAC efficiency, gross margin, and operational leverage. If you are profitable but growing slowly, the focus is on identifying and investing in the growth drivers that are being underweighted.
Important: improving your Rule of 40 score by cutting costs without improving NRR is likely to reduce your valuation, not increase it. Buyers can see through cost-reduction-driven EBITDA improvement, and they will discount a business that has traded growth investment for short-term margin.
The Metric Combination That Commands a Premium
The buyers who pay the highest multiples in the lower middle market are buying companies that score well on both metrics simultaneously, with NRR as the floor and the Rule of 40 as the differentiator among companies that clear the NRR threshold.
The premium combination in 2026:
| Metric | Premium Threshold |
|---|---|
| NRR | Above 110% |
| Rule of 40 | Above 40, balanced between growth and margin |
| Growth rate | Above 25% year over year |
| Gross margin | Above 70% |
| CAC payback | Under 18 months |
Companies that meet all five criteria consistently attract multiple qualified buyers and run competitive processes that drive valuations to the top of the range for their ARR band. Companies that meet three or four are still competitive. Companies that meet fewer than three typically trade at or below median multiples regardless of how the individual metrics compare to industry benchmarks in isolation.
Frequently Asked Questions
What is the Rule of 40 in SaaS? The Rule of 40 is a metric calculated by adding a SaaS company’s annual revenue growth rate to its EBITDA margin. A score above 40 indicates that the company’s combined growth and profitability profile is considered healthy by investors and acquirers.
What is net revenue retention (NRR) in SaaS? Net revenue retention measures the percentage of revenue retained from existing customers over a twelve-month period, including expansions, contractions, and churn. NRR above 100% means existing customers are spending more than they did a year ago in aggregate.
Which matters more for SaaS valuation, Rule of 40 or NRR? In the lower middle market in 2026, NRR is generally more decisive because it measures revenue durability — which buyers are underwriting more carefully than in previous years. A company with NRR above 110% and a Rule of 40 score of 35 typically commands a higher multiple than one with NRR of 90% and a Rule of 40 score of 45.
What is a good NRR for a lower middle market SaaS company? NRR above 110% is considered strong and supports premium valuations. NRR between 95% and 110% is acceptable and near median. NRR below 90% typically triggers meaningful buyer scrutiny and valuation discounts.
What is a good Rule of 40 score for M&A purposes? A Rule of 40 score above 40 is generally considered healthy. Scores above 50, particularly when driven by a balance of growth and margin rather than pure cost-cutting, command premium multiples in LMM tech M&A.
What EV/ARR multiples are LMM SaaS companies trading at in 2026? Median EV/ARR multiples in the lower middle market range from approximately 2.5x for companies below $5M ARR to 6x–8x for companies between $30M and $75M ARR. Top-quartile companies — those with NRR above 110%, Rule of 40 above 40, and strong growth — consistently achieve multiples 1.5x to 2x above the median for their ARR band.
Telegraph Hill Advisors is a boutique investment bank based in San Francisco specializing in technology M&A. We have advised on 250+ transactions for founder-led SaaS and technology companies and regularly help founders understand how their metrics position them before going to market. If you want to understand where your company sits in this framework, we are happy to have that conversation.