Co-Investment Opportunities: When to follow a general partner and when to walk away
Co-investments have become one of the more talked-about topics in single family office circles.
The appeal is real, but so are the risks
Co-investments offer several potential advantages over traditional fund investing. The most obvious is economics — fee structures on co-investments are typically potentially more favorable, which may improve net returns over time. Beyond fees, co-investments may offer Single Family Offices something that blind-pool fund structures can’t: the ability to express views on a specific industry, geography, and company type. If you’ve spent thirty years building and operating businesses in healthcare, taking a direct co-investment position in a healthcare company alongside a GP you trust is a fundamentally distinctive proposition.
There’s also the matter of capital deployment. Co-investments can help accelerate the pace at which committed capital gets to work, may help reduce the drag of the J-curve that tends to frustrate family offices in the early years of a private markets program.
The risk profile of co-investments are different and often require specialist knowledge and expertise. Firstly, GP selection is crucial and investors need to ensure they are partnering with GPs that have a track record of delivering value for their LPs. Second, the due diligence timeframe on a co-investment opportunity is almost always compressed. Investors have to quickly form a view, complete their analysis, and invest. There is little room for error.
Five ways family offices actually do this
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Building an internal team with dedicated co-investment professionnals who can source, evaluate, and execute transactions entirely in-house.This is the most resource-intensive option and may be a cost-efficient model, if you are doing a lot of deals and can staff it properly, but the operational and administration demands are real: you need people with the right skills, established processes, and the ability to move fast when a deal is live.
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Maintaining internal decision-making authority while bringing in a trusted external advisor or using an extension of staff service to assist with due diligence.This is a more common arrangement for mid-sized family offices and could preserve control and keeps costs lower than a fully external solution, but it still requires you to have your own GP relationships and the internal capacity to act quickly, with the risk that constrained internal resources can slow execution and limit access.
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If building an internal team isn’t feasible, a third-party co-investment fund could remove most of the administrative burden.The trade-off is an additional layer of fees and the loss of any discretion over specific investments - you’re outsourcing both the sourcing and the decision-making.
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We believe a separately managed account or fund-of-one sits in the middle: you work with an external manager who runs the co-investment program on your behalf, but you retain the ability to set the objectives, constraints, and risk parameters.Permitted geographies, deal size limits, sector preferences - these can all be defined up front, potentially giving you a tailored portfolio without requiring a full internal build-out, with the risk of increased manager dependence and reduced day-to-day visibility.
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The fifth approach: investing in a sidecar vehicle alongside a GP fund that you’re already committed to.These allow you to take an additional stake in specific portfolio companies within the existing fund structure, typically on favorable fee terms. The limitation is obvious — you’re dependent on the GP’s judgment, and your opportunities are confined to what they source for the main portfolio.
Some important considerations
Whatever structure you use, the same due diligence questions apply every time an opportunity lands on your desk.
Start with the GP. Is this deal squarely within their area of demonstrated capability? A buyout firm that has spent twenty years acquiring industrial distribution businesses is on solid ground when they bring you a co-investment in that sector. The same firm pivoting to a growth equity deal in software is a different conversation. GPs perform best when they’re operating in territory they know, and co-investment opportunities that sit outside a manager’s historical strengths should be viewed with caution regardless of how the deal is packaged.
Then ask why you’re being offered this. Strong GPs recognise the value in strengthening their relationship with LPs who regularly invest with them and could offer co-investment access as part of a genuine relationship. We believe the quality of your GP relationships is ultimately the quality of your deal flow.
Think hard about your own capacity to evaluate the deal in the time available. Co-investments require a different analytical skill set than evaluating a fund - you’re making a company-level judgment, not a manager-level one. And unlike fund commitments, they don’t allow for the diversification of a single misjudgement across a portfolio of companies.
Consistency matters more than selectivity
Perhaps the most underappreciated aspect of building a co-investment program is the virtue of consistency. In our experience, family offices that typically do well in co-investments are those that have deployed capital steadily across vintage years and deal sizes rather than concentrating activity when markets feel favourable and going quiet when they don’t. Vintage year diversification in co-investments is not just about risk management - it’s about building relationships with GPs who come to see you as a reliable, professional partner rather than an opportunistic one.
Co-investments can be a meaningful component of sophisticated family office portfolios however, attractive economics don’t compensate for inadequate due diligence, the wrong GP relationships, or a structure that doesn’t match your actual capabilities. If you rush past the foundations, you may learn an expensive lesson about why the fees in the main fund were worth paying.
When co‑investments may not be the right fit
Sarah Gresty has been the Single Family Office proposition leader at Mercer since 2025, supporting Family Offices globally.
She has 25‑years experience in Financial Services, focused on Family Offices, Private Banking and Wealth Management.
Sarah holds two degrees in Computer Science from the University of Liverpool and Lancaster University, and an MBA from Alliance Manchester Business School. She is a member of the Chartered Institute for Securities and Investments with a Level 6 diploma.
is a Senior Alternatives Investment Director at Mercer, leading Alternative Investment programs across private markets in Europe. Previously, he managed a $6bn Global Fixed Income portfolio as a Portfolio Manager at AustralianSuper. He is a Fellow of the Institute of Chartered Accountants Ireland, Chartered Tax Advisor, and CFA® charterholder.
is a senior advisor on thematic investments within Mercer’s Global Structural Trend Team, with over 20 years of experience in wealth management, family offices, and thematic investing. He holds three university degrees and is a CFA Charterholder and Chartered Wealth Manager.