What active managers do
Active fund managers employ analysts and portfolio managers to research companies, assess macro trends, and construct portfolios of securities they believe will outperform the market. They charge annual management fees (typically 0.5–1.5% in the UK) to cover these costs. In principle, active management can add value through superior analysis, earlier identification of undervalued companies, better risk management, and tactical asset allocation. In practice, the challenge is formidable: financial markets are highly competitive, with thousands of professional analysts scrutinising the same companies simultaneously. Any publicly available information is quickly reflected in prices, making genuine informational edges rare and temporary. Active managers must not just identify the right investments — they must do so consistently enough to cover their fee premium over the index.
The maths of active management
The arithmetic of active management makes the odds challenging. All investors together hold all available securities — so before fees, the average active investor must earn the market return. After fees, the average active investor must underperform the market by the amount of those fees. This is not an opinion; it is arithmetic (the "Sharpe arithmetic of active management"). Some active managers will outperform — but identifying them in advance, rather than chasing historical performance, is itself an unsolved problem. Past performance of active funds shows almost no persistence beyond what chance would predict; the top quartile of fund managers in one five-year period shows no meaningful tendency to remain in the top quartile in the next.
When active management might make sense
Active management has a stronger case in genuinely less efficient markets: small-cap stocks in emerging markets, private credit, or highly specialised niches where fewer analysts compete and informational edges can persist. In the most analysed, liquid markets (S&P 500 large-caps) the evidence against active management is most overwhelming. Some investors also choose active management for reasons beyond pure return: ESG integration, concentrated exposure to a specific thesis, or access to strategies unavailable through index funds (private equity, long/short). The key discipline is being honest about whether you are choosing active management for genuine reasons or simply because it feels more comfortable than passive.
“In investing, you get what you don’t pay for. The surest way to capture market returns is to minimise the costs you pay to try to beat them.” — John Bogle, founder of Vanguard
What this means for you
For most people, a core portfolio of low-cost passive index funds — covering global equities and global bonds — provides the simplest, most evidence-based path to long-term wealth building. You can add active strategies around the edges if you have specific reasons, but the default should be passive, and the burden of proof lies with any active strategy to justify its additional cost. The most powerful argument for passive: it frees you from the need to constantly monitor performance, analyse fund managers, and make ongoing active decisions — time and mental energy you can spend elsewhere.