Asset Allocation: How to Decide Your Investment Mix

Choosing how to split your money across stocks, bonds, cash, and other assets is an important decision you make as an investor. Research from Vanguard has shown that more than 90% of a portfolio’s return variability is explained by its asset allocation, more than any specific stocks or funds you pick. The good news is you don’t need a finance degree to get it right. Using a simple framework based on your age, goals, and risk tolerance, you can choose an allocation that works best for you. In this guide, we’ll walk through what asset allocation is, why it matters, how to choose a mix, and the difference between strategic and tactical approaches.

What is asset allocation?

Asset allocation is how your investment portfolio is spread across different assets, such as stocks, bonds, and cash. The percentages you hold in each asset can determine how much growth potential and risk your portfolio has. The right split depends on your age, financial goals, and risk tolerance.

Your investment portfolio is everything you own across all your accounts. Your asset allocation is the recipe for that portfolio, or the percentages you put into each asset. Diversification is the practice of spreading your money across many investments within and across different assets so you’re not over-reliant on any single one. You can think of allocation as the big picture and diversification as the detail.

Why your asset allocation matters

Different assets can behave differently over time. According to Vanguard, a portfolio that’s invested in only bonds has averaged about 6% annual returns since 1926, while a portfolio that’s invested in only stocks has averaged about 12%, in line with the stock market’s long-term average return. That’s a meaningful difference, and over decades of investing it can add up to dramatically different outcomes for the same dollar contributed.

But higher returns can come with bigger swings. That same all-stock portfolio has had years where it lost more than 40% of its value. An all-bond portfolio’s worst year was a loss of about 8%. Your allocation is what sets the trade-off between growth potential and how much volatility you’ll experience along the way. It’s also the foundation of a diversified portfolio, the principle behind Modern Portfolio Theory (Harry Markowitz’s Nobel-winning work showing that combining assets that behave differently can reduce risk without giving up much return).

A look at the three main assets

Most allocation frameworks come down to how you split your money among the three broad assets: Stocks, bonds, and cash or cash equivalents.

Stocks

Stocks represent ownership in a company. They have the highest long-term growth potential out of the three, but also have the most volatility. Most investors hold stocks through low-cost ETFs (exchange-traded funds) or index funds and mutual funds rather than picking individual companies.

Bonds

Bonds are loans you make to a government or company. The borrower pays you interest and returns your principal at the end of the loan’s term. Bonds generally have lower returns than stocks, but also tend to lose less value when stocks fall, which can be helpful for stabilizing a portfolio.

Cash and cash equivalents

Cash and near-cash investments like savings accounts, money market funds, and short-term Treasury bills generate modest returns but barely move in value. They’re useful for money you’ll need soon, or as a buffer for the years right before and after retirement.

For deeper coverage of each, see our asset classes guide. The rest of this article focuses on how to mix them.

What shapes your asset allocation

Three personal factors shape your allocation more than anything else: Your time horizon, risk tolerance, and financial goals.

Your time horizon

How long until you need the money? The longer your time horizon, the more volatility you can afford to ride out, which generally means a bigger allocation to stocks. Money you need in three years should mostly be in cash and bonds. Money you won’t touch for 30 years can be invested far more aggressively, in part because compound interest has more time to do its work. To see your potential, try our compound interest calculator to see how it adds up.

Your risk tolerance

How comfortable are you with the value of your portfolio dropping? This is partly emotional (how would you feel watching your account fall 30%?) and partly financial (could you afford to wait years for the recovery?). Our guide to risk tolerance walks through how to assess yours honestly.

Your financial goals

Different goals can call for different mixes. Retirement usually points to a more stock-heavy allocation early in your career. A house down payment in 5 years calls for something safer. Many investors hold separate allocations for different goals, often across different account types.

Asset allocation by age

Age isn’t the only factor, but it’s a useful starting point because it tracks with your time horizon. The general principle is when you have decades away from retirement, you can hold more stocks because there’s more time to recover from market dips. As retirement gets closer, you typically shift towards bonds and cash to protect the savings you’ve already built.

The rule of 100

A common rule of thumb you could try is the Rule of 100. Subtract your age from 100, and the result is the percentage of your portfolio that should be in stocks. The rest goes into bonds and cash.

A 30-year-old would target about 70% stocks and 30% bonds and cash. A 60-year-old would target about 40% stocks and 60% bonds and cash. Some experts even consider the Rule of 110 or 120 to account for longer life expectancies, since money may need to last 30+ years in retirement. Under the Rule of 110, that same 60-year-old would target 50% stocks. These are guidelines, not hard rules. Your actual mix should reflect your full picture, including any other income sources, debt, risk tolerance, and specific goals you’re investing for.

A typical allocation by decade

As a rough guideline, here’s how allocations often shift over a typical investing life:

• In your 20s: about 90% stocks, 10% bonds and cash
• In your 30s: about 80% stocks, 20% bonds and cash
• In your 40s: about 70% stocks, 30% bonds and cash
• In your 50s: about 60% stocks, 40% bonds and cash
• In your 60s: about 50% stocks, 50% bonds and cash
• In your 70s and beyond: about 30 to 40% stocks, 60 to 70% bonds and cash
   

These are typical starting points, not personal advice, and your situation may call for something different. Acorns builds a recommended portfolio based on your age, goals, and risk tolerance, and adjusts it automatically if you make any changes or your portfolio drifts too far from your target allocation.

Strategic vs. tactical asset allocation

Once you’ve chosen a target mix, there are two broad approaches to managing it over time.

Strategic asset allocation

Strategic asset allocation sets a long-term target mix based on your goals and risk tolerance, and sticks with it. When market movements push your target mix off course, you rebalance to get it back to where you started. The point is consistency. You’ve decided what mix fits your situation, and you don’t change it based on short-term market noise.

Strategic allocation is the default for most investors because it doesn’t require you to predict the market, and it’s harder to mess up than the alternative.

Tactical asset allocation

Tactical asset allocation actively shifts the mix in response to shorter-term market conditions. If a tactical investor thinks stocks are overvalued, they might temporarily move more money into bonds. When they think conditions have improved, they shift back.

Tactical allocation can boost returns when it’s done well, but it’s also harder to execute. It requires accurate short-term market forecasting (which is difficult even for seasoned investors), and small mistakes can be costly. It’s more common among professional active managers than among individual investors.

Dynamic asset allocation

Dynamic asset allocation sits between the two. The mix shifts over time, but the shifts are driven by your changing life situation rather than market predictions. The most common example is an age-based or glide-path approach, where stocks gradually decrease and bonds increase as you age. Target date funds and Acorns Later’s age-based portfolios both work this way.

If you’re an individual investor, strategic allocation (with age-based or dynamic adjustments over the long term) can be a great approach to go with.

Common asset allocation strategies

Most allocation frameworks fall into three buckets, each suited to different time horizons and risk tolerances.

Income (conservative)

A heavily bond-weighted portfolio (often 20 to 30% stocks and 70 to 80% bonds and cash) is designed to preserve what you have and generate steady income. It’s a common choice in retirement and for money you’ll need within a few years.

Balanced (moderate)

A balanced portfolio splits roughly evenly between stocks and bonds. A classic example is the 60/40 portfolio (60% stocks and 40% bonds), because it has the potential to grow, but have bonds to help balance volatility. It can suit investors with a mid-to-long-term horizon (often 40s and 50s) who want growth without experiencing the volatility in an all-stock portfolio.

Growth (aggressive)

A growth portfolio is stock-heavy (often 80/20 or even 100% stocks). It has the highest long-term growth potential but also the biggest swings, so it generally suits younger investors who have decades until they need the money.

Historical performance by allocation

Here’s how different mixes have performed over nearly a century, according to Vanguard:

Source: Vanguard, calculations through December 31, 2024. Past performance is not a guarantee of future returns.

The numbers tell a clear story. Higher stock allocations have produced higher long-term returns, at the cost of bigger losses in bad years. There’s no allocation that wins on both dimensions, only allocations that fit different situations.

Asset allocation funds and ETFs

If you’d rather not build your own allocation, asset allocation funds (also called balanced funds, target date funds, or LifeStrategy funds) hold a pre-set mix of stocks, bonds, and cash in a single fund. You buy one share, and instantly own a diversified allocation. Asset allocation ETFs work the same way in ETF form.

These funds are convenient, but they’re one-size-fits-all. A robo-advisor like Acorns Invest goes a step further by building and managing a portfolio matched to your specific risk profile, then rebalancing it as you go.

When to review and rebalance

Most financial experts recommend reviewing your allocation at least once a year, or any time your mix has drifted more than about 5 to 10 percentage points from your target. For example, if a strong stretch in the stock market pushes your portfolio from 70% stocks up to 80%, portfolio rebalancing means selling some stocks and buying bonds to get back to your target mix. It helps keep your strategic allocation from drifting into something riskier (or more conservative) than you intended.

Robo-advisors handle this automatically, so you don’t have to remember to do it.

Getting the right allocation with Acorns Invest

The framework above is everything you need to choose your own allocation. If you’d rather not handle it yourself, Acorns Invest does the work for you.

When you sign up, Acorns asks about your age, income, and goals, then recommends an expert-built ETF portfolio matched to your risk profile. Acorns also rebalances your portfolio automatically when your mix drifts off target. You can get started with as little as $5, and the Acorns Bronze plan is $3/month. If you want more control, the Acorns Gold plan unlocks Custom Portfolios, which let you add individual stocks and ETFs on top of your already-diversified base portfolio. For retirement-specific allocation, Acorns Later helps you invest for retirement with a Traditional, Roth, or SEP IRA.

Explore the right plan for you at Acorns.

Frequently asked questions

What is asset allocation in simple terms?

Asset allocation means spreading your investments across different assets, typically stocks, bonds, and cash. The split determines how much risk and growth potential your portfolio has, and the right split depends on your age, goals, and how much risk you can tolerate.

What is the Rule of 100 in investing?

The Rule of 100 is a simple guideline for asset allocation: Subtract your age from 100, and the result is the percentage of your portfolio that should be in stocks. For example, a 30-year-old would hold 70% stocks and 30% in bonds and cash. Some experts even consider the Rule of 110 or 120 to account for longer life expectancies.

What's the difference between strategic and tactical asset allocation?

Strategic asset allocation sets a long-term target mix and rebalances back to it periodically. Tactical asset allocation actively shifts your target mix in response to short-term market conditions. Most individual investors consider strategic allocation because it requires less active management and is harder to get wrong.

What is a 60/40 portfolio?

A 60/40 portfolio holds about 60% stocks and 40% bonds. It's a popular balanced allocation because stocks provide growth potential while bonds help balance short-term volatility. It’s a mix that suits moderate-risk investors and those in their 40s and 50s.

How often should I rebalance my asset allocation?

Most financial experts recommend reviewing your asset allocation at least once a year, and rebalancing if your mix drifts more than 5%-10% from your target. Robo-advisors like Acorns Invest handle rebalancing automatically.

What's the best asset allocation for retirement?

There's no single right answer, but most retirees hold a mix to help protect against major losses while still offering enough growth potential to outpace inflation. A common starting point is 40%-60% stocks and 40%-60% bonds and cash, with the exact split depending on how long the savings need to last and your other income sources.

Can I use an asset allocation fund instead of building a portfolio myself?

Yes. Asset allocation funds (sometimes called balanced funds, target date funds, or LifeStrategy funds) hold a pre-set mix of stocks, bonds, and cash in a single fund. They’re a hands-off way to get a diversified allocation without picking individual investments. A robo-advisor like Acorns Invest takes this a step further by building and managing a personalized portfolio for you.