Accredited investors arriving at the pre-IPO secondary market for the first time often treat it like a public stock screen: find the name you like, decide on a dollar amount, and submit an order. In a private market marketplace, that mental model breaks down quickly when you realize that private positions cannot be trimmed next week if your view changes, cannot be hedged with listed options, and may not produce a liquidity event for years. If you're still building foundational context on how pre-IPO investing works before thinking about position sizing, review the complete guide to pre-IPO investing. Position sizing in private markets requires a different framework than public equities — one built around illiquidity tolerance, not just conviction.
Start with your liquidity budget, not your return target
The foundational question is not 'how much do I want to own of this company?' It is 'how much capital can I afford to have inaccessible for three to seven years without affecting my financial life?' That number — call it your illiquidity budget — is the ceiling for your entire pre-IPO allocation. Everything else flows from there.
Many experienced private-market investors set an illiquidity budget of 10–20% of their investable assets, meaning capital not tied up in primary residence, retirement accounts, or emergency reserves. Inside that budget, individual names rarely exceed 20–25% of the private allocation, which translates to 2–5% of total investable assets per issuer. Those are not rules — they are calibration points. Your specific numbers depend on your income stability, existing private holdings, and tax situation.
Why illiquidity compounds the standard concentration risk
In public markets, concentration risk — the danger of too much exposure to one stock — can be managed dynamically. You can trim a position that has grown too large, sell covered calls to generate income while reducing risk, or buy protective puts. None of those tools exist cleanly for private company stakes.
A secondary sale is technically available, but it is not instantaneous. Most marketplaces require 1–5 business days to settle a transaction, and finding a willing buyer at an acceptable price is not guaranteed. If you own a large position in a single private name and the company's business deteriorates, you may find the secondary market for that name thin or bid-less precisely when you most want to exit.
This asymmetry — liquid on the way in, illiquid on the way out — is the defining feature of private secondary investing. Position sizing must account for it from day one.
A practical sizing framework
Step 1: Define your total private allocation
Before looking at any individual issuer, decide what percentage of your investable assets you are willing to place in private markets in total. This is a personal decision that should involve your financial and tax advisors. Common starting points range from 5% for investors new to private markets to 30% or more for those with deep experience and high income stability. Write that number down — it becomes the denominator for everything that follows.
Step 2: Apply a per-name ceiling
Within your private allocation, cap any single issuer at a percentage that reflects your conviction and the company's risk profile. A company that has been public before (a re-listing scenario) or that has disclosed revenues and growth rates is lower information-risk than a pre-revenue or very early-stage name. Higher information quality can justify a slightly higher per-name weight. A reasonable range for most buyers is 15–30% of the private allocation per name, scaling down as uncertainty increases.
Step 3: Account for existing exposure you may already have
If you hold index funds or diversified ETFs, check whether they contain any of the 28 issuers on Limen Markets' marketplace — particularly Rocket Lab and Reddit Pro, which are or were recently public. If you work at a company with equity in the same sector as your target private name, that correlation is also exposure. A buyer with significant compensation tied to AI infrastructure probably does not need a full private allocation to both Cohere and Glean.
Step 4: Stress-test the position at zero
Private companies fail. Secondary buyers do not have the information advantages that lead investors in primary rounds possess. Before finalizing a position size, ask yourself: if this company returned zero, would I be financially okay and emotionally capable of continuing my investment program? If the honest answer is no, the position is too large.
Structure affects your effective concentration, not just your dollar exposure
The vehicle through which you hold a private position changes your effective exposure in ways that raw dollar amounts do not capture. An SPV interest means you are exposed to the underlying company AND to the SPV manager's decisions about when and how to liquidate. A forward contract introduces counterparty risk — if the counterparty fails before the company goes public, your claim on shares may be unsecured. A direct transfer gives you clean cap table ownership but requires you to navigate transfer restrictions and ROFR — right of first refusal — processes yourself.
Right of first refusal, or ROFR, gives the company (and sometimes existing shareholders) the right to purchase your shares at the agreed transaction price before the transfer completes. ROFR is exercised rarely, but when it is exercised, it can unwind a deal you believed was settled. That tail risk is part of your effective exposure even if it does not show up in a dollar figure.
Diversifying across names on the same marketplace
One practical advantage of a marketplace with breadth — Limen Markets covers 28 issuers across consumer fintech, enterprise software, defense technology, AI infrastructure, and aerospace — is that diversification within the private allocation is achievable without opening accounts at multiple platforms. Splitting a private allocation across four to six issuers in different sectors reduces the risk that any single company's setback dominates your private portfolio.
That said, diversification is not a substitute for position-level discipline. Five positions that are each too large relative to your illiquidity budget is still an over-concentrated private portfolio. The framework above applies at the individual name level regardless of how many names you hold.
If you are ready to map your allocation across available issuers, the marketplace shows current supply with real-time pricing, minimum position sizes starting at $25,000 per name, and structure details — including whether a given listing is direct or SPV-wrapped. For a deeper primer on how secondary prices form before you commit to any specific name, the bid-ask discovery explainer covers the mechanics from first principles.