Every allocator has a due diligence checklist. Few have a due diligence process that would have caught the failures that actually cost institutions money. The uncomfortable truth of manager selection is that the disasters rarely come from the numbers on the tear sheet — they come from the things the tear sheet does not show: the star PM quietly interviewing elsewhere, the strategy running at triple its capacity, the operational shortcut that turns a bad quarter into a gating event. Performance gets you the meeting. Everything else determines whether you should stay.
Start with the base rate, because it disciplines the entire exercise. S&P's SPIVA scorecards for year-end 2025 found that not a single one of the 22 US equity categories tracked saw a majority of active managers beat their benchmarks over 15 years. In 2025 alone — the fourth-worst year for active large-cap managers in SPIVA's 25-year history — 79% underperformed the S&P 500. You are selecting from a population where the modal outcome is underperformance. That does not mean selection is futile; it means your process has to be good enough to beat those odds, and most processes are performance-chasing with extra steps.
Start With the Business, Not the Backtest
The first diligence failure is sequencing: allocators analyze returns before they analyze the business, which is like marrying someone for their wedding photos. The business questions come first. Who owns the firm, and what happens when the founder retires or dies? How is the investment team compensated — on asset growth, on performance, on firm profitability? (Asset-linked bonuses in a capacity-constrained strategy are a confession.) What is the firm's revenue breakeven, and how close is it? A manager one bad year from insolvency does not make patient investment decisions.
Capacity is the question most allocators ask and almost none verify. Every strategy has a capacity beyond which its edge decays — the manager will name a number, usually round and reassuring. The diligence is in the triangulation: compare the stated capacity to the liquidity of the actual holdings, the turnover rate, and the market impact implied by position sizes. A small-cap manager running $8 billion with 80% turnover in names trading $5 million a day is not running a small-cap strategy; they are running a liquidation in slow motion. Ask for the capacity analysis in writing, with the assumptions. If it does not exist, you have your answer.
Then the team. Investment management is a people business with a retention problem the industry prefers not to discuss. Ask not just who is on the team but who left in the last five years and why — departures of senior analysts are a leading indicator that shows up in performance with a two-year lag. Ask about non-competes and garden leave: a firm that cannot retain talent without legal handcuffs is telling you something. And ask the PM what they would do if the strategy doubled in size overnight. The good answers involve closing; the bad ones involve "scaling the process."
The Five Questions That Change the Conversation
If you take one thing from this piece, take these five questions. They are the ones that make managers uncomfortable, which is precisely why they work.
One: "Show me a period when your process told you to do something painful, and you did it." Every strategy has a story about discipline; few have the trade tickets. You are testing whether the process binds when it costs money.
Two: "What is your edge, specifically, and what would make it disappear?" Vague answers — "deep fundamental research," "our culture" — are not edges. An edge is a structural advantage: an information asymmetry, a behavioral discipline, a liquidity provision, a time-horizon arbitrage. And every edge has an expiration condition. A manager who cannot name theirs does not have one.
Three: "Walk me through your worst drawdown — not the market's, yours." You want the attribution: what broke, what they learned, what changed. Managers who blame "unprecedented conditions" for the third time are describing their process, not the market.
Four: "Who are your largest investors, and what would happen if the largest two redeemed?" Concentration risk in the client base is the operational risk nobody models. A fund that gates because two allocators left is not a victim of bad luck.
Five: "Show me the personal capital." Managers who eat their own cooking — substantial personal investment in the strategy, on the same terms — behave differently under stress. It is not a guarantee. It is a filter, and a good one.
The Unsexy Part That Saves You
Operational due diligence is where the bodies are buried, and it is chronically under-resourced because it is boring. The checklist is well-established — independent administrator, Big Four auditor, separation of trading from valuation, documented compliance, background checks on principals, service-provider concentration — but the value is in the exceptions, not the checks. Why did they change administrators twice in three years? Why is the auditor a firm you have never heard of? Why does the COO also run trading? Every fraud and most blowups in the industry's history had operational tells visible in advance to anyone who looked past the returns.
Here is the quotable summary: due diligence is not a process for finding reasons to invest — it is a process for finding reasons not to, pursued until none remain. Most allocator processes are structured to confirm an initial enthusiasm. Invert it. Assign someone the explicit job of killing the idea, reward them for finding the flaw, and watch how many "compelling opportunities" fail to survive contact with their own business model.
The managers worth hiring can survive that process. That is rather the point.
Manager selection is a research discipline. managerresearch.com is available for acquisition by the firm that will define it. Inquiries: info@primedomaincapital.com.