What is asset allocation?
Asset allocation is how you split your money across different types of investment — mainly shares, bonds and cash — based on the job each one does. Shares aim for growth, bonds add stability, and cash gives quick access. Your timeframe and how calmly you handle ups and downs shape the mix. This split shapes your results more than which individual shares you hold.
What do shares, bonds and cash each do?
Each asset type has a role. Shares (also called equities or stocks) are the growth engine — they can rise a lot over years, but they also fall hard in bad spells. Bonds are loans to governments or companies that pay interest; they tend to move more gently and add ballast when shares wobble. Cash — money in a savings account or a money-market fund — barely grows, but it is there when you need it and it does not drop in value.
Thinking in roles — growth, stability, access — is more useful than thinking about any single company. The blend of these three is what people mean by asset allocation.
How do timeframe and comfort with ups and downs shape the mix?
Two things quietly drive most allocations. The first is timeframe: money you will not touch for twenty years can ride out share-market falls, so a larger share slice has time to recover. Money you need in two years has little time to recover, so stability and access matter more.
The second is temperament — how you feel watching a balance drop 20% in a month. Someone who would lose sleep over that may prefer a gentler mix, even over a long horizon. There is no single mix that fits everyone, and this page does not point to a correct one for you.
Why does allocation matter more than picking individual shares?
Studies of long-run returns keep landing on the same point: the split between shares, bonds and cash explains far more of how a portfolio behaves than the choice of which specific shares sit inside it. A calm 60/40 mix of a broad shares fund and bonds can shape your journey more than swapping one company for another.
This is why many beginners start from the allocation decision — often using low-cost index funds or a single global tracker — rather than hunting for individual winners. The mix comes first; the holdings that fill each slice come second.
What is rebalancing, in one line?
Rebalancing is simply moving your mix back to its chosen percentages after markets have pushed it out of shape — commonly once a year, or when the drift becomes large.
A worked example
Suppose you have £10,000 and describe a mix of 60% shares, 30% bonds and 10% cash. That is £6,000 in a shares fund, £3,000 in bonds and £1,000 in cash. Over a strong year the shares rise to £7,800 while bonds and cash hold steady, so your pot is now £11,800 — and shares have quietly grown to 66% of it. Rebalancing back to 60/30/10 would mean moving about £720 out of shares and into bonds and cash, returning the mix to the split you first chose.
Common questions
Is there one right asset allocation?
No. Asset allocation is personal, and this page does not point to a correct split for you. The mix people choose reflects their timeframe, their need for access to cash, and how calmly they cope with falling prices. A longer horizon and steadier nerves often lean toward more shares.
What is rebalancing, in simple terms?
Rebalancing means bringing your mix back to your chosen split after markets move it. If shares grow faster than bonds, they end up a larger slice than you planned. Rebalancing trims that slice back toward your chosen percentages, usually once a year or when the drift becomes large.
Does asset allocation apply inside an ISA?
Yes. An ISA is a wrapper that shelters your money from UK tax, not an investment itself. Inside it you still choose how much sits in shares, bonds or cash. The allocation idea works the same way; the ISA simply changes the tax treatment of what your mix earns.
Where to next
General information to help you understand investing, not advice about your situation. Figures are illustrative and the rules can change - always check gov.uk or your provider for the latest.