Why Avoid Single Stocks and Invest in Mutual Funds Instead?

Why is it so important to avoid buying single stocks and invest in mutual funds instead? Because one company can lose most of its value and never come back, while a fund spreads your money across dozens or hundreds of companies. Most individual stocks actually trail the overall market over their lifetimes, so a diversified fund lets you capture the market’s return without betting everything on picking the rare winner.

That’s the short answer. But this question hides a bigger lesson, one I learned the hard way (after 20+ years of investing).

I’m a dentist. Years ago, I sprained my wrist on a family ski trip, and for the first time I realized my entire income depended on my hands. If I couldn’t treat patients, the money stopped. That’s exactly the same problem as owning one stock: everything rides on one thing going right.

Let’s walk through the data, the different types of funds, what fees really cost you, and why this idea matters far beyond your brokerage account.

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What the Data Says About Owning Single Stocks

Most articles on this topic just tell you single stocks are “risky.” That’s true, but it helps to see how risky. The research here is pretty eye-opening.

Most Individual Stocks Lose to Treasury Bills

Hendrik Bessembinder, a finance professor at Arizona State University, studied the lifetime returns of nearly every U.S. stock going back to 1926. He found that 58% of stocks didn’t beat the return on Treasury bills over their lives, and just over 4% were responsible for pushing the market’s overall return above Treasury bills.

Think about that. Treasury bills are about as boring as investing gets, and most stocks couldn’t beat them.

All of the $35 trillion in wealth stocks created above Treasury bill returns between 1926 and 2016 came from just 1,092 companies, or about 4.3% of the roughly 26,000 stocks that traded. His newer research looked even further. Across 29,078 stocks from 1926 to 2023, 51.6% had negative compound returns, meaning slightly more than half lost money over their lifetime.

About 4 in 10 Stocks Suffer a Permanent Crash

J.P. Morgan ran a similar study they called “The Agony and the Ecstasy.” They looked at about 13,000 stocks that were in the Russell 3000 at any point from 1980 to 2014 and found that 40% suffered a drop of 70% or more from their peak with little recovery afterward.

That’s not a temporary dip you wait out. That’s a loss that sticks.

The same analysis found that two thirds of stocks underperformed the Russell 3000 Index itself, and more than 40% had negative absolute returns. So even if you avoid a total disaster, odds are your one stock lags the broader market.

Even the Experts Don’t See It Coming

Here’s the part you should pay attention to. In J.P. Morgan’s 2024 update, healthcare and biotech was the sector with the largest number of catastrophic decliners. Many of us are drawn to healthcare stocks because we think we understand the industry, but understanding medicine and predicting a stock price are two very different skills.

And Wall Street analysts didn’t catch these collapses either. When those catastrophic loss stocks were at their peak, analyst consensus leaned heavily toward strong buy ratings, and most weren’t trading at crazy valuations. If professionals with full research teams can’t spot the landmines, it’s tough for a busy doctor to do it between patients.

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5 Reasons Mutual Funds Make More Sense Than Single Stocks

Now that you’ve seen the numbers, here’s why a diversified fund is the better choice for most people building wealth in the stock market.

1. Diversification Protects You From One Bad Company

When you own one stock, one bad earnings report, lawsuit, or accounting scandal can wipe out years of savings. Remember Enron? Many of its employees held a big chunk of their retirement in company stock, and when it collapsed in 2001, that money disappeared along with their jobs.

A fund holding hundreds of companies barely notices when one of them fails. That’s the whole point.

2. You Don’t Have to Find the Needle in the Haystack

Since such a small slice of stocks drives nearly all market gains, picking a few stocks means you’ll probably miss the winners. Bessembinder put it plainly: the only way to be sure you own the future big gainers is to own all the stocks through a broad fund.

You don’t need to be right about which company wins. You just need to own the market.

3. It Saves You Time

Researching individual companies takes real work: reading financial statements, tracking management, following competitors. Most people don’t have that kind of time, and honestly, you shouldn’t have to spend your evenings doing it.

A diversified fund does the spreading for you. Your time is better spent on your family, your health, and building other income streams.

4. It Protects You From Yourself

This one’s huge. When you own a single stock, every headline feels personal, and it’s easy to panic sell during a drop or chase a hot stock after it’s already run up.

A broad fund (I like the S&P 500 fund) still goes up and down, but it’s less emotional. You’re less likely to make a costly decision because one company had a bad week.

5. Cost Is Still a Factor, Just a Different One

Older advice said single stocks were expensive because of trading commissions and high share prices. That’s mostly outdated now. Most major brokerages charge zero commission on stock trades, and fractional shares let you buy a slice of an expensive stock.

So today, the cost argument isn’t about commissions. It’s about fund fees, which can quietly eat a big chunk of your returns. More on that next.

Not All Mutual Funds Are Created Equal

Here’s where many articles get it wrong. Saying “buy mutual funds” isn’t enough, because a mutual fund can be cheap and broad or expensive and narrow.

Actively Managed Mutual Funds

These funds have a manager picking stocks they think will beat the market. The problem is that most don’t. In 2025, 79% of active large cap U.S. stock funds underperformed the S&P 500, one of the worst years in the 25 years S&P has tracked this.

And it gets worse over time. Over the 20 years ending in December 2025, 92.89% of actively managed large cap funds trailed the S&P 500. Picking a manager who’ll beat the market is a lot like picking a single stock that will.

Index Funds and ETFs

Index funds don’t try to beat the market. They simply hold the companies in an index, like the S&P 500 or the total U.S. stock market, and they usually charge very low fees. ETFs (exchange traded funds) work similarly but trade throughout the day like a stock.

Both give you broad diversification at a low cost. That’s why so many investors use them as the core of their stock portfolio.

Sector and Specialty Funds

Some funds only hold one industry, like technology or biotech. These are diversified across companies but concentrated in one area, so if that sector takes a hit, the whole fund goes down with it.

A biotech fund isn’t much safer than owning a handful of biotech stocks. Always check what’s inside the fund before you assume you’re diversified.

What a 1% Fee Really Costs You

A fee of 1% sounds tiny. But over 20 years, it adds up to real money. Here’s a simple hypothetical: $100,000 invested once, earning 8% a year before fees, held for 20 years.

Annual Fee	Value After 20 Years	Lost to Fees vs. 0.05%
0.05%	About $461,800	None
0.50%	About $424,800	About $37,000
1.00%	About $387,000	About $74,800
1.50%	About $352,400	About $109,400

Hypothetical example for illustration only. Assumes 8% annual return before fees with no additional contributions. Actual returns will vary.

That 1% fee costs you roughly $75,000 on a single $100,000 investment. Now picture that across a whole career of contributions. Fees matter, and they’re one of the few things you can actually control.

Single Stocks vs. Mutual Funds vs. Index Funds

Here’s a quick side by side to make the differences clear.

Feature	Single Stocks	Actively Managed Mutual Funds	Index Funds and ETFs
Diversification	None (one company)	Moderate to high	High (hundreds to thousands of companies)
Risk of Permanent Loss	High	Low to moderate	Low (for broad market funds)
Typical Annual Cost	No ongoing fee	Often 0.5% to 1% or more	Often under 0.2%
Time Required	High (ongoing research)	Low	Very low
Goal	Beat the market with one company	Beat the market with a manager	Match the market
Emotional Pressure	High	Moderate	Lower

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Clearing Up a Few Common Myths

There’s a lot of confusing advice out there on this topic. Let’s fix a few of the most common mistakes.

“Mutual Funds Guarantee You Won’t Lose Money”

No investment is a sure thing. A diversified fund lowers the risk that one company sinks you, but it can still drop in value, sometimes a lot. Anyone promising a guaranteed result is someone you should be careful with.

“The Safe Choice Means Mediocre Returns”

This one trips people up. A broad fund gives you the market’s return, and as the SPIVA data shows, that’s a return most professional stock pickers fail to beat over time. Matching the market isn’t settling. Over long periods, it’s actually beating most of the people trying to beat it.

“Your 401(k) Can Only Hold Mutual Funds”

Not quite. Many 401(k) plans offer mutual funds, but some also include collective investment trusts, target date funds, or a brokerage window with more choices. Check your plan documents to see what’s actually available to you.

What a Stock Fund Can’t Protect You From

Here’s the part most articles leave out, and it’s where the real lesson starts.

A stock fund protects you from company risk. If one business fails, you’re fine. But it doesn’t protect you from stock market risk. When the whole market falls, your fund falls with it. In the 2008 financial crisis, the S&P 500 lost roughly half its value from peak to bottom, and even the most diversified stock fund went right down with it.

It also doesn’t protect you from asset class risk. If every dollar you own sits in the stock market, you’re still concentrated, just in a bigger basket. You’ve diversified across companies, but not across the different ways money can be made.

The Bigger Lesson: Don’t Put Everything on One Bet

Remember my sprained wrist? Lying there after that ski trip, I realized I’d been doing the exact same thing most people do with a single stock. I’d put everything on one bet, and that bet was my hands.

If I couldn’t treat patients, my income stopped. No backup plan. No other stream coming in.

That’s when I picked up Robert Kiyosaki’s Cashflow Quadrant and started to understand how wealthy people think. They don’t rely on one income source. They build income producing assets that pay them whether they show up to work or not.

Diversify Your Income, Not Just Your Portfolio

The logic that tells you to avoid one stock also tells you to avoid relying on one asset class, and on one income stream. For me, that meant building passive income outside dentistry, mainly through mobile home parks and real estate syndications. Those assets produce cash flow each month and behave very differently from the stock market.

You don’t have to follow my exact path. But it’s worth asking yourself a simple question: if your ability to work disappeared tomorrow, what would still pay you?

Where Funds Fit in a Work Optional Plan

Diversified funds can be a solid part of your plan, especially inside retirement accounts. But they’re one piece of the puzzle, not the whole thing. Most doctors reach work optional status faster when they combine smart stock market investing with income producing assets that pay them today, not just at 65.

FAQs

Is it bad to own any individual stocks at all?

Not necessarily. Some investors keep a small slice of their portfolio for individual stocks they enjoy following. The danger comes when a single stock makes up a big share of your net worth, because one bad outcome can set you back years.

What’s the difference between a mutual fund and an index fund?

A mutual fund pools money from many investors to buy a basket of investments. An index fund is a type of mutual fund (or ETF) that simply tracks a market index instead of having a manager pick stocks. Index funds usually cost much less.

How many stocks do I need to be diversified?

Studies vary, but owning a few dozen stocks across different industries gets you some diversification. Even then, you could easily miss the small group of winners that drive most market gains. A broad fund holding hundreds or thousands of companies solves that problem in one step.

Are ETFs better than mutual funds?

Neither is automatically better. ETFs often have lower minimums and can be more tax efficient in a taxable account, while mutual funds are common in 401(k) plans. What matters most is what the fund holds and what it charges.

Does diversification mean I can’t lose money?

No. Diversification lowers the risk of losing money because of one company, but a stock fund can still fall when the overall market drops. That’s why it helps to think about diversifying across asset classes and income streams too.

This is not financial or tax advice. Consult your advisor or accountant before making any investment decisions.

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