The Biggest Investing Mistakes Beginners Make (and How to Avoid Them)

The patterns that quietly drain new investors, and how to sidestep them.

Are you trying to time when to buy and sell?

Timing the market is one of the most common - and most costly - mistakes beginners make. You see the news about market dips, worry about buying at the "wrong time," and wait for the perfect moment that never comes. Meanwhile, investors who simply started investing get the benefit of regular growth over years.

The data is clear: missing just 10 of the best days in the market over a 20-year period cuts your returns roughly in half. And here’s the thing - nobody can reliably predict which days those will be. Not professional fund managers, not analysts, not anyone.

Instead, focus on investing regularly through ups and downs. This approach, called pound-cost averaging, actually helps you. You buy more shares when prices are low and fewer when they’re high - the opposite of what most panicked investors do.

Is your money spread across just one or two investments?

Putting all your money into one stock, one sector, or one fund type is a concentration risk. If that investment stumbles, your whole portfolio stumbles with it. Beginners often fall into this trap after reading about one successful company or fund.

Proper diversification means spreading your money across different investment types - UK shares, international shares, bonds, and property funds. Within each category, you want variety too. A simple solution is using a low-cost tracker fund that holds hundreds of companies across different sectors and countries.

This doesn’t guarantee profits, but it smooths out the ups and downs and protects you from devastating losses if one investment fails.

Do you panic sell when markets dip?

Market corrections happen. They’re normal, not disasters. Yet many beginners see a 10% or 15% fall and immediately sell everything - locking in losses right before the recovery. They’ve turned a temporary setback into a permanent one.

When markets fall, you should actually feel slightly calmer, not more anxious. If you’re buying regularly through investments like ISAs or pensions, those dips mean your regular contributions buy more shares at lower prices. That’s a good thing for long-term investors.

Set your investment timeline realistically before you start. If you need the money within 5 years, the stock market isn’t the right place for it anyway. But if you’re investing for 10+ years, short-term falls barely matter.

Are you chasing last year’s winning investment?

The fund that gained 30% last year is everywhere in the news. So you buy it, expecting more of the same. What you don’t realize is that past performance genuinely doesn’t predict future results. Market leaders rotate constantly. The red-hot tech fund becomes a laggard. The boring defensive fund suddenly outperforms.

Chasing performance also makes you buy high and sell low - the exact opposite of what builds wealth. Instead, stick to a diversified plan and rebalance occasionally to maintain your target mix.

Every investment must have a clear reason in your portfolio, not just "it went up last year."

Are you ignoring fees and charges?

A difference of 0.5% per year in fees doesn’t sound like much. Over 30 years, it cuts your final pot by roughly a third. This is why so many beginners end up frustrated - they’re making sensible investment choices but paying middlemen who quietly drain returns.

Always check the ongoing charges figure (OCF) for any fund you buy. For most beginners, anything above 0.75% per year is expensive. Tracker funds often charge 0.1-0.3%. Platform fees matter too - some brokers charge £100+ per year for accounts worth less than £10,000.

The good news: low-cost investing is easier than ever. Several platforms charge nothing, and index tracker funds are incredibly cheap.

Are you investing money you’ll need in the next few years?

This isn’t really about mistakes - it’s about using the wrong tool for the job. Stock market investments can fall 20%, 30%, or more in a bad year. If you need that money in 2027, a market crash in 2026 destroys your plans.

Before you invest anything, build an emergency fund in a savings account - at least 3 months of expenses, ideally 6. Only then does investing money you won’t touch for 5+ years make sense.

For money you need soon (5 years or less), use cash savings or fixed-rate savings bonds. They’re boring compared to investing, but they’re reliable.

Do you check your portfolio constantly?

Watching your investments daily is a surefire way to panic at the wrong moments. Markets bounce around constantly. What feels like a disaster on Tuesday is forgotten by Friday. Checking every day trains your brain to react emotionally rather than think strategically.

Set yourself a rule: check your investments quarterly or annually. Once a year is genuinely enough for long-term investors. This protects you from making emotional decisions based on short-term noise.

Where Mona Fits

Mona makes it simple to avoid several of these mistakes at once. Instead of managing multiple investments across different platforms and paying separate fees everywhere, you get one straightforward approach - diversified, low-cost, automated. You set up regular contributions once, then let it work without the temptation to tinker constantly.

The Bottom Line

The biggest investing mistakes aren’t usually about picking the wrong fund or buying at the wrong price. They’re about the emotional decisions you make when markets shift. Time in the market beats timing the market. Diversify, keep fees low, invest regularly, and resist the urge to check constantly. That combination, followed consistently, is how most successful long-term investors build wealth.

Start investing with a plan, not panic. Open your Mona account today.

For impartial information and guidance on investing, visit MoneyHelper.org.uk.

Join Mona’s early access waitlist

Join the waitlist

All articles

The Biggest Investing Mistakes Beginners Make (and How to Avoid Them)

The patterns that quietly drain new investors, and how to sidestep them.

Are you trying to time when to buy and sell?

Timing the market is one of the most common - and most costly - mistakes beginners make. You see the news about market dips, worry about buying at the "wrong time," and wait for the perfect moment that never comes. Meanwhile, investors who simply started investing get the benefit of regular growth over years.

The data is clear: missing just 10 of the best days in the market over a 20-year period cuts your returns roughly in half. And here’s the thing - nobody can reliably predict which days those will be. Not professional fund managers, not analysts, not anyone.

Instead, focus on investing regularly through ups and downs. This approach, called pound-cost averaging, actually helps you. You buy more shares when prices are low and fewer when they’re high - the opposite of what most panicked investors do.

Is your money spread across just one or two investments?

Putting all your money into one stock, one sector, or one fund type is a concentration risk. If that investment stumbles, your whole portfolio stumbles with it. Beginners often fall into this trap after reading about one successful company or fund.

Proper diversification means spreading your money across different investment types - UK shares, international shares, bonds, and property funds. Within each category, you want variety too. A simple solution is using a low-cost tracker fund that holds hundreds of companies across different sectors and countries.

This doesn’t guarantee profits, but it smooths out the ups and downs and protects you from devastating losses if one investment fails.

Do you panic sell when markets dip?

Market corrections happen. They’re normal, not disasters. Yet many beginners see a 10% or 15% fall and immediately sell everything - locking in losses right before the recovery. They’ve turned a temporary setback into a permanent one.

When markets fall, you should actually feel slightly calmer, not more anxious. If you’re buying regularly through investments like ISAs or pensions, those dips mean your regular contributions buy more shares at lower prices. That’s a good thing for long-term investors.

Set your investment timeline realistically before you start. If you need the money within 5 years, the stock market isn’t the right place for it anyway. But if you’re investing for 10+ years, short-term falls barely matter.

Are you chasing last year’s winning investment?

The fund that gained 30% last year is everywhere in the news. So you buy it, expecting more of the same. What you don’t realize is that past performance genuinely doesn’t predict future results. Market leaders rotate constantly. The red-hot tech fund becomes a laggard. The boring defensive fund suddenly outperforms.

Chasing performance also makes you buy high and sell low - the exact opposite of what builds wealth. Instead, stick to a diversified plan and rebalance occasionally to maintain your target mix.

Every investment must have a clear reason in your portfolio, not just "it went up last year."

Are you ignoring fees and charges?

A difference of 0.5% per year in fees doesn’t sound like much. Over 30 years, it cuts your final pot by roughly a third. This is why so many beginners end up frustrated - they’re making sensible investment choices but paying middlemen who quietly drain returns.

Always check the ongoing charges figure (OCF) for any fund you buy. For most beginners, anything above 0.75% per year is expensive. Tracker funds often charge 0.1-0.3%. Platform fees matter too - some brokers charge £100+ per year for accounts worth less than £10,000.

The good news: low-cost investing is easier than ever. Several platforms charge nothing, and index tracker funds are incredibly cheap.

Are you investing money you’ll need in the next few years?

This isn’t really about mistakes - it’s about using the wrong tool for the job. Stock market investments can fall 20%, 30%, or more in a bad year. If you need that money in 2027, a market crash in 2026 destroys your plans.

Before you invest anything, build an emergency fund in a savings account - at least 3 months of expenses, ideally 6. Only then does investing money you won’t touch for 5+ years make sense.

For money you need soon (5 years or less), use cash savings or fixed-rate savings bonds. They’re boring compared to investing, but they’re reliable.

Do you check your portfolio constantly?

Watching your investments daily is a surefire way to panic at the wrong moments. Markets bounce around constantly. What feels like a disaster on Tuesday is forgotten by Friday. Checking every day trains your brain to react emotionally rather than think strategically.

Set yourself a rule: check your investments quarterly or annually. Once a year is genuinely enough for long-term investors. This protects you from making emotional decisions based on short-term noise.

Where Mona Fits

Mona makes it simple to avoid several of these mistakes at once. Instead of managing multiple investments across different platforms and paying separate fees everywhere, you get one straightforward approach - diversified, low-cost, automated. You set up regular contributions once, then let it work without the temptation to tinker constantly.

The Bottom Line

The biggest investing mistakes aren’t usually about picking the wrong fund or buying at the wrong price. They’re about the emotional decisions you make when markets shift. Time in the market beats timing the market. Diversify, keep fees low, invest regularly, and resist the urge to check constantly. That combination, followed consistently, is how most successful long-term investors build wealth.

Start investing with a plan, not panic. Open your Mona account today.

For impartial information and guidance on investing, visit MoneyHelper.org.uk.

Join Mona’s early access waitlist

Join the waitlist

All articles