One of the most quoted pieces of investing wisdom comes from legendary fund manager Peter Lynch: “Invest in what you know.” The idea is simple, the products and services you use daily give you a ground-level view of what is resonating with consumers, sometimes before Wall Street catches on. Lynch was able to average a 29.2% annual return managing Fidelity’s Magellan Fund from 1977 to 1990. [i] But there is a meaningful difference between using consumer familiarity as a starting point and letting it drive the entire investment decision. For private market investors, understanding that distinction could be the difference between a smart edge and a costly blind spot.
Invest in What You Know: Smart Strategy or Dangerous Bias?
The Case For: Why Familiarity Can Be a Genuine Advantage
Lynch’s philosophy was rooted in a real insight: everyday consumers often spot trends before professional analysts do. If you notice a product gaining traction in your daily life, a brand you keep recommending to friends, an app you can no longer imagine living without, that observation carries signal. You are seeing real-world demand firsthand rather than reading about it in a research report.
In the private market context, this advantage can be even more pronounced. Startup investing happens early, often before a company has significant media coverage or institutional analyst attention. An investor who uses a product, understands its value proposition, and can speak to why customers keep coming back has a meaningful head start on due diligence. They know the product works, they understand the customer experience, they may even have insight into how the company stacks up against competitors.
Lynch himself discovered Dunkin’ Donuts, not through a Wall Street report, but after being impressed by the coffee as a customer. He used that observation as a starting point, then dug into the financials. The key phrase is “starting point.”
The Case Against: Where Consumer Enthusiasm Becomes a Liability
The problem arises when familiarity with a product gets confused with understanding of the business. Loving an app does not mean you understand its unit economics. Using a service regularly does not tell you whether the company is profitable, how much it costs to acquire each new customer, or whether its valuation reflects realistic growth assumptions. Consumer enthusiasm and investment merit are not the same thing, and conflating the two has burned even sophisticated investors.
Research consistently shows that investors exhibit familiarity bias, gravitating toward companies with recognizable brands even when financial fundamentals do not support the investment.[ii] This bias can be particularly acute in startup investing, where valuations are set subjectively and the gap between a compelling product and a sound investment can be very wide. A packed restaurant might be losing money on every meal. A fast-growing app might be acquiring customers at a cost that makes the business fundamentally unprofitable. The product experience rarely tells you any of that.
There is also the risk of overlooking what you don’t know. Sectors that are less visible to everyday consumers, industrial automation, enterprise software, defense technology, can offer compelling investment opportunities precisely because they fly under the radar. An investor anchored to familiar consumer products may systematically miss these categories.
How to Use Familiarity as a Tool, Not a Crutch
The goal is not to ignore your consumer experience but to use it correctly. Lynch never suggested buying a product you love without doing the work. He recommended studying the company’s financials, understanding its competitive position, and evaluating whether the price reflected the growth potential. The consumer observation opens the door; the due diligence decides whether you walk through it.
For private market investors, a few questions can help separate genuine insight from bias when trying to invest in what you know:
- Does the product have broad appeal, or do I just personally love it? A niche product with a passionate but small user base may not support the growth trajectory needed for a successful product.
- Do I understand how the company actually makes money? Revenue model, margins, and customer acquisition costs matter as much as product quality.
- Is the valuation grounded in fundamentals? A product you love at a $500 million valuation is a very different investment than the same product at a $50 million valuation.
- Am I diversifying, or am I only investing in companies I personally use? Concentrating a portfolio around familiar consumer brands can create blind spots and reduce exposure to less visible but potentially more attractive opportunities.
What This Means for Private Market Investors
Consumer familiarity can be a genuine edge in private market investing, but only when it is treated as a starting point rather than a conclusion. Consumer-informed investing can look like this: you encounter a product that impresses you, you notice strong organic demand around it, and you use that observation as the first step in a deeper process of due diligence. The other side looks like this: you love the product, you assume others will too, and you invest without looking at the financials or questioning the valuation.
Lynch’s insight was never that familiarity alone was enough. It was that familiarity, combined with real research, could give individual investors an edge that professionals lacked. In private markets, that combination can be just as powerful, and the discipline to maintain it can be just as important.
Final Thoughts
Loving a product is a perfectly reasonable place to start when evaluating an investment. It means you understand the customer experience, you can speak to the value proposition, and you have a firsthand view of demand. But it’s only the beginning of the analysis, not the end. Investors can use the “invest in what you know” philosophy to use customer insight to ask better questions, not skip them. In private markets, where valuations are subjective and information is limited, that discipline can help research investment opportunities.
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Want to learn more about investing in startups? Check out the following MicroVentures blogs to learn more:
- The Psychology of Investing: Navigating Investment Bias
- Biases in Investing
- What’s It Worth? Navigating Inflated Startup Valuations
- Developing Your Investment Thesis
- Due Diligence Red Flags
[i] https://www.ii.co.uk/analysis-commentary/how-invest-best-peter-lynch-ii534756
[ii] https://www.investorsedge.cibc.com/en/learn/investing/portfolio-strategies/overcome-familiarity-bias.html
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The information presented here is for general informational purposes only and is not intended to be, nor should it be construed or used as, comprehensive offering documentation for any security, investment, tax or legal advice, a recommendation, or an offer to sell, or a solicitation of an offer to buy, an interest, directly or indirectly, in any company. Investing in both early-stage and later-stage companies carries a high degree of risk. A loss of an investor’s entire investment is possible, and no profit may be realized. Investors should be aware that these types of investments are illiquid and should anticipate holding until an exit occurs.
