10 common investing mistakes (and how to avoid them)

FOMO investing — fear of missing out — is buying an asset mainly because its price has already risen sharply and you are afraid of being left behind.

"GameStop is up 800% this week. My friend tripled his money. I need to get in NOW." — a retail investor, January 2021

What actually happened — They buy GameStop at $380. Two weeks later it's $50 — an 87% loss in 14 days. The very thing that made it feel exciting — the rapid rise — was the reason it was already too late.

The rule: don't buy what has already moved — By the time something is on the news and everyone is excited, the opportunity has usually passed. Rising prices attract attention; attention drives more buying; late buyers fuel the final surge and then absorb the crash.

Panic selling is dumping your investments during a market decline out of fear, which turns a temporary paper loss into a permanent, locked-in one and usually means missing the recovery.

"Markets are down 35% in the 2020 crash. It's going to zero. I need to get out before I lose everything." — a frightened investor, March 2020

What actually happened — They sell everything at the bottom of the 2020 crash in March 2020. The market recovers 100% within 5 months and hits all-time highs by August. Selling locked in the loss and missed the entire recovery — someone who held through did nothing and came out ahead.

The rule: crashes are temporary; selling makes them permanent — You only actually lose money when you sell. If you hold through a crash and the underlying companies are still sound businesses, time often heals the portfolio. Selling at the bottom converts a paper loss into a real, locked-in loss.

Over-concentration is holding too large a share of your portfolio in a single stock or theme — often more than 5–10% in one company — so one bad outcome can sink the whole portfolio.

"I work in tech. I understand tech. I'm putting 80% of my savings into one tech company I know well." — a tech employee, 2021

What actually happened — They put 80% of their $50,000 portfolio — $40,000 — into one mid-cap tech company. The company misses earnings by 5%, the stock falls 60%, and it never recovers — a $24,000 loss. The same $40,000 in a tech ETF would have fallen 30% temporarily before recovering.

The rule: no single company should make or break you — Professional investors rarely put more than 5% of a portfolio in one company. Diversification isn't about limiting upside — it's about surviving being wrong about one company. And being wrong happens, even to experts.

Fee drag is the long-term cost of high investment fees: even a 1–1.5% annual charge compounds against you and can quietly consume a large share of your lifetime returns.

"I'm investing in a managed fund that beats the market! The fee is just 1.5% per year — that seems small." — a first-time fund buyer

What actually happened — $50,000 at 8% return for 30 years: Low-cost index fund (0.03% fee) → $499,000. Managed fund (1.5% fee) → $331,000. The 'small' 1.5% fee costs $168,000 over 30 years. The fee didn't feel real. The $168,000 loss is very real.

The rule: fees compound just like returns — in reverse — A 1.5% annual fee on $50,000 seems like $750. But that $750 could have been compounding for 30 years. Over a lifetime of investing, 1.5% vs 0.03% is the difference between retiring comfortably and retiring very comfortably.

Market timing is trying to buy at the bottom and sell at the top by predicting short-term moves — something almost no one does reliably, because the best days tend to cluster right after the worst ones.

"The market feels too high right now. I'll wait for a dip, then put my money in." — a would-be market timer, every year since 2013

What actually happened — They keep their savings in cash, waiting for a crash that will let them buy in cheaply. Years pass and the market grinds higher; the 'dip' they finally buy is still well above where they started waiting. The best trading days also tend to cluster right after the worst ones, so sitting in cash to dodge a drop usually means missing the rebound too.

The rule: time in the market beats timing the market — No one reliably predicts short-term tops and bottoms — not even professionals. Across recent 20-year periods, an investor who missed just the handful of best days would have given up a large share of their total return compared with someone who stayed fully invested. Contributing on a schedule beats waiting for a perfect entry that never announces itself.

Investing without a safety net means putting money you may soon need into the market with no cash buffer, so an emergency can force you to sell at the worst possible moment.

"I put my whole savings into the market — emergency fund included. I'll figure it out if something comes up." — an investor with no safety net

What actually happened — Six months later their car dies and their hours get cut — right as the market is down 20%. With no cash buffer, they're forced to sell at the worst possible moment to cover the bills, turning a temporary paper loss into a permanent one. The same downturn did no lasting damage to investors who had three to six months of expenses set aside and never had to sell.

The rule: invest only money you won't need soon — Before investing, keep an emergency fund of three to six months of expenses in cash or a high-yield savings account, and never invest money you may need within the next few years. Investing with borrowed money — or rent money — forces you to sell on the market's schedule, not yours, and the market rarely cooperates.

Leverage is investing with borrowed money or derivatives such as options, which magnifies losses exactly as fast as gains and can cost you more than you originally put in.

"My account is up. If I trade on margin and buy some call options, I can double my gains." — a first-year investor

What actually happened — They borrow to buy more and add short-dated options for extra leverage. A modest 15% dip in their stocks becomes a 40% loss once the borrowing is counted, and the options expire worthless before the stock recovers. Leverage multiplies losses exactly as fast as gains — and a margin call can force a sale at the very bottom.

The rule: skip leverage and options until you truly understand them — Margin, options and other leveraged products magnify both directions and add ways to lose that simple buy-and-hold investing doesn't have. A large share of bought options expire worthless, and margin can cost you more than you put in. Beginners build wealth far more reliably with un-leveraged, diversified funds.

Yield chasing is buying the highest-yielding stocks or funds on the headline payout alone — but an unusually high yield is often a warning sign that the price has collapsed, not a reward.

"This stock yields 12% and that fund advertises a huge payout. Free income — why buy anything else?" — a yield-chasing investor

What actually happened — They load up on the highest-yielding stocks they can find. Within a year, two of them cut their dividends and their share prices fall further — the high yield was a warning sign, not a gift. A double-digit yield often exists precisely because the price has already collapsed on fears the payout can't last.

The rule: an unusually high yield is a red flag, not a reward — Dividend yield rises as a share price falls, so the highest yields often mark the most troubled companies; the same logic applies to any 'too good to be true' rate. Check whether the payout is actually sustainable — covered by earnings and cash flow — rather than buying on the headline number alone.

Failing to reinvest dividends means taking payouts as cash instead of using them to buy more shares, which switches off one of the biggest engines of long-term compounding.

"I take my dividends as cash and spend them. It's only a few percent a year — how much can it matter?" — a dividend investor

What actually happened — They pocket every dividend instead of reinvesting it. Over decades the difference is enormous: a large share of the stock market's long-run total return has historically come from dividends being reinvested and compounding on themselves. By spending them, they quietly switched off one of the biggest engines of long-term growth.

The rule: reinvest dividends while you're still building wealth — Reinvested dividends buy more shares, which pay more dividends — the compounding loop behind much of the market's long-run return. Most brokers let you turn on automatic dividend reinvestment for free. Take dividends as income later, when you're living off the portfolio — not while you're still growing it.

Cash drag is leaving money you intend to invest sitting in cash for too long, so it misses the market's average upward drift — the cost of trickling a lump sum in over years instead of investing it promptly.

"I came into a lump sum, but investing it all at once feels reckless. I'll spread it over the next five years." — an investor with a windfall

What actually happened — They leave most of their windfall in cash and ease it in over years. Because markets rise more often than they fall, historically investing a lump sum promptly has, more often than not, beaten spreading it out — the cash left waiting simply misses the market's average upward drift. Spreading it out can calm the nerves, but doing it for years 'to be safe' usually just costs return.

The rule: know the difference between investing from income and from a windfall — Investing from a regular paycheck? Dollar-cost averaging — a fixed amount on a schedule — is exactly right, and you should keep it going through downturns, when your money buys the most shares. Already have a lump sum? The evidence favors investing it promptly into a diversified portfolio rather than holding it in cash for years waiting for the 'right' moment.