Asset Allocation: What Determines 90% of Your Investing Results

Most people pour their energy into the wrong question. They agonize over which stock to buy, which fund is hottest, which coin is about to moon. Meanwhile they ignore the decision that actually drives their results.

That decision is your asset allocation: how you split your money across the big buckets, mainly stocks and bonds. And the research is blunt about how much it matters.

The 90% that actually matters

A landmark study by researcher Gary Brinson found that roughly 90% of a portfolio’s results come from asset allocation, and only about 10% from the specific investments you pick inside each bucket.

Read that again. The stock-picking, the fund-hunting, the thing everyone spends all their time on? That’s the 10%. The boring decision of “how much in stocks versus bonds” is the 90%.

What asset allocation actually is

Asset allocation just means dividing your portfolio across different types of investments, each with its own risk and reward:

• Stocks are ownership in companies. Historically the best long-term performer, but volatile. You have to expect and stomach a 20 to 30% drop every so often. That is the price of admission.
• Bonds are loans to governments or companies. Lower returns, but far steadier. They are the shock absorber that keeps your portfolio from swinging as hard when stocks fall.
• Cash (savings, money market) is your buffer. Low return, but there when you need it.

There are others (real estate, commodities like gold, crypto), but for most people building wealth, the stock-and-bond split is the decision that counts.

Why the mix beats the pick

Two reasons.

First, it manages risk. If everything you own is one hot sector and that sector crashes, you crash with it. A sensible mix means a hit in one place can be cushioned by another. You are not betting the farm on a single guess.

Second, and this is the one people miss, the right mix is the one you can actually live with. The best portfolio on a spreadsheet is worthless if you panic-sell it in the first downturn. This ties straight to one of my core principles: optimize for sleep, not returns. Your allocation isn’t really about squeezing out the last percent. It’s about building a portfolio you can hold through a scary market without bailing at the bottom.

How to actually set your split

A simple, common rule of thumb: 120 minus your age is roughly the percent to keep in stocks, with the rest in bonds. At 30 that’s about 90% stocks, because you have decades to ride out the dips. At 60 it’s about 60%, to protect what you’ve built. It’s a starting point, not gospel.

The good news for most Canadians: you don’t have to build this by hand. An all-in-one ETF bakes the allocation right in and rebalances itself:

• VEQT is 100% stocks (aggressive, long time horizon)
• VGRO is about 80% stocks, 20% bonds
• VBAL is about 60% stocks, 40% bonds

Pick the one that matches your age and your stomach, buy only that one, and you’ve made the 90% decision in about 30 seconds. (More on picking a fund in Index Funds and ETFs.)

The takeaway

Stop obsessing over the 10%. The next time you’re tempted to chase the perfect stock or the fund everyone’s talking about, remember Brinson’s number: how you split between stocks and bonds does about 90% of the work, and it’s a decision you can make once and mostly leave alone.

Get the allocation right, get it inside the right accounts, automate it, and let it run. Then go run your Nomad Number to see where that steady, boring plan actually takes you.

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Not sure what mix is right for your age and goals? The 4-week coaching program helps you set an allocation you’ll actually stick with, then automate the whole thing. Or start free with the tools.