Multi-Asset vs Single-Asset Investing
The honest version of this comparison is uncomfortable: over the past two decades a single-asset portfolio in global stocks beat a diversified one on total return, and beat it by a wide margin. A £100,000 invested in stocks alone at the roughly 10.5% annualised return of the period 2004 to 2024 would have grown to about £737,000. A diversified mix of stocks, bonds, gold and cash at roughly 7.5% would have grown to about £425,000, around 58% of the stock-only result. Diversification wins nothing on paper; it wins on the requirement the concentrated version places on you, which is sitting through losses that most people cannot sit through.
What concentration actually demands
Concentration works when you have a genuine edge, which is rarer than it sounds. A professional analyst who studies companies for a living can justify a handful of positions. A property investor who knows one neighbourhood deeply can justify betting on it. Someone who has read a few articles about stocks cannot, because the edge is not knowledge, it is an ability to value something independently of the market consensus.
The risk is symmetrical. The portfolio of your five best ideas outperforms your twenty best ideas only if the five really are better. When they are not, the loss is concentrated too, and the two most recent lessons are easy to name: a single stock can fall 70% in a year, and a single crypto project can go to zero. A diversified portfolio absorbs either as a bad quarter.
What diversification gives up
Diversification trades a lower ceiling for a higher floor. Over the 20 years to 2024, global stocks delivered most of their gain in about a fifth of the days, and a diversified portfolio still held a big share of those days. The difference is the drawdowns. A stock-heavy portfolio fell roughly 50% in the 2008-2009 crisis and around a third in the 2020 crash. A mix of stocks, bonds, gold and cash fell far less in both, because the non-equity holdings were not falling with it.
The catch is behavioural, and it is the one that decides real outcomes. An investor who sold during the 2008 crash locked in the full loss. That happened to a large share of the people who held concentrated portfolios, because a 50% drawdown is not a number you experience calmly. The diversified investor lost less, sold less, and was still buying at the bottom.
When we model the two portfolios through the 2008 and 2020 drawdowns with the deposits people actually make, the concentrated version only wins for the minority who hold throughout. The version that delivers for most people is the one with the smaller worst case, because the worst case is the moment the decision gets made.
Who the concentrated version is actually for
Concentration is defensible only when all three of these are true, and they are a stricter test than most people apply to themselves. First, genuine expertise: the ability to value a holding independently of the market consensus, which for stocks means reading the accounts, not the headlines. Second, the time to monitor: a portfolio of five stocks needs regular review of earnings and valuations, and a concentrated property position needs active management. Third, the record: having held through a large drawdown without selling, because every concentrated strategy will ask it of you eventually.
Someone with a demanding job and a monthly glance at the portfolio fails all three, and diversification fits the attention they can actually spare. Investors within ten years of retirement face the same conclusion regardless of expertise, because a 50% drop at age 62 delays retirement by years and the sequence of returns risk is not something a good eye for value fixes.
The middle ground is not a compromise
A core-satellite structure keeps most of the return of concentration with most of the safety of diversification. The core, roughly 70 to 80% of the portfolio, holds broad index funds and stable assets. The satellites, the remaining 20 to 30%, hold the positions you can genuinely argue about: a stock you have researched, a property you know, a crypto project you understand.
The arithmetic is what makes it defensible. If the satellites are 20% of the portfolio and they all go to zero, the portfolio falls 20%. Painful, recoverable. If they double, they add meaningful return without requiring you to bet everything on being right. You get the upside of your best ideas and the survival of the diversified core.
The decision that matters more than the split
Both approaches fail in the same place: the investor who cannot measure the portfolio correctly. A single-asset investor holding only stocks needs one dashboard. A multi-asset investor holds a brokerage, an exchange, a savings account, a metals dealer and a property, each reporting performance differently. If you cannot answer what the whole portfolio returned this year, the theoretical benefit of diversification is not doing its job.
Returns are only comparable when they are built the same way, which means recording every deposit, withdrawal and income payment as a capital flow. A stock gain, a savings rate and a rental yield calculated on different bases cannot be compared at all. The true returns explainer shows the same £100,000 built both ways, and the best portfolio tracker guide covers what to look for in the software.
The honest test is whether you have held through a 40% drawdown before, because that is what the strategy will ask of you. Most people who say they would hold through one have not been tested. If the answer is not certain, the diversified core with a satellite position is the version that keeps working while you find out.
This page compares the two approaches and their historical outcomes; it is not personal advice, and the right choice depends on your expertise, time and tolerance for drawdowns. Past returns are not a guide to future performance.
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