There is no single right number of private investments to hold. A portfolio built entirely of early-stage startups might behave like one built from later-stage secondaries, and the number of positions that makes each one resilient is different. What does carry across every private portfolio is the reason the question matters in the first place: concentration risk. In private markets, a handful of positions can come to define your outcome, and once you are in, you usually cannot trade your way out. So the question "What role might private investments play in a portfolio? " is really a question about risk tolerance, and how long you are willing to wait to find out. This guide walks through how investors think about that tradeoff — concentration risk in private markets, position sizing, and what role holding private investments could mean.