DIY investing: the most common mistakes and how to avoid them

2. An unsuitable portfolio

Your portfolio should reflect your risk tolerance, investment timeline, and long-term objectives. Many DIY investors make the mistake of being too aggressive, chasing high-risk investments that could lead to big losses – or being too conservative, missing out on growth and leaving their money vulnerable to inflation.

Research backs this up: a Vanguard study found that 90% of a portfolio’s long-term returns are driven by asset allocation, not stock picking or market timing. Yet, many DIY investors struggle with diversification – over-concentrating in one asset class or failing to rebalance over time.

Asset allocation is key: the right mix of growth assets like global equities and defensive assets like cash and bonds helps balance risk and return. Without a clear strategy, you risk volatility or underperformance.

Many DIY investors opt for active funds, hoping to outperform the market. Studies like the S&P Global’s SPIVA Report show, however, that a significant percentage of active funds fail to outperform the S&P 500 in the long term. Active funds are often more expensive than passive or tracker funds, and these higher fees can erode your returns. Instead, consider using low-cost passive funds that track the market, as they have been shown to offer better long-term performance at a lower cost.

A smarter approach

• Diversify across asset classes, sectors, and regions to reduce risk.
• Rebalance regularly to maintain your target asset mix.
• Align your portfolio with your financial goals and risk tolerance for sustainable growth.
• Get expert guidance – a financial adviser in Cirencester or the Cotswolds, like Abode Financial Planning, can help you optimise your investments.

By ensuring your portfolio is properly diversified and regularly adjusted, you can manage risk and maximise growth over time.

3. Trying to time the market

Many DIY investors believe they can predict market highs and lows, but market timing is tricky. Often, it results in buying high and selling low, which reduces potential gains.

The risks of market timing are clear: J.P. Morgan research shows that missing the 10 best days in the market over 20 years can cut your total return by more than half. The best days often follow the worst, so sitting out can lock in losses rather than help you benefit from recoveries.

Dimensional: The Cost of Trying to Time the Market

A smarter approach

Instead of trying to time the market, follow a disciplined, long-term strategy:

• Use pound cost averaging (PCA) – investing a fixed amount regularly to reduce volatility and risk.
• Stay invested – let your investments grow through market cycles.
• Avoid emotional reactions to short-term fluctuations.

As Warren Buffett, one of the greatest investors of all time, wisely puts it:

“the stock market is a device for transferring money from the impatient to the patient.”

A financial adviser can help you stay focused on your long-term goals, avoiding the temptation to react impulsively.

4. No withdrawal strategy

Many DIY investors focus on building their portfolio but fail to plan how to withdraw funds efficiently in their retirement planning. Without a structured approach, you risk:

• Depleting your savings too quickly
• Paying unnecessary taxes
• Missing opportunities to maximise income streams
• Sequencing risk – withdrawing funds during a market downturn, which can lock in losses and significantly reduce the longevity of your retirement savings. Take a look at our article on investment strategies for retirement to learn more about how sequencing risk can impact your withdrawals.

Retirees also underestimate inflation, unexpected healthcare costs, and market downturns, which can lead to quicker depletion of funds than expected.

A smarter approach

A solid withdrawal strategy creates financial security:

• Use tax-efficient strategies to reduce tax liabilities.
• Agree on a sensible withdrawal figure – a financial adviser can help to calculate the likelihood of you running out of money based on historical market data.
• Sequence withdrawals wisely – use different accounts at optimal times.
• Adjust withdrawals – monitor and adapt your income based on market conditions, with the help of a financial adviser.

A financial adviser can ensure you have a sustainable, tax-efficient withdrawal plan tailored to secure your retirement.

5. Ignoring tax efficiency

Taxes can erode your investment returns, yet many DIY investors overlook tax-efficient strategies. A survey by the International Accounting Bulletin revealed that a staggering 45% of UK investors are unaware of the taxes applicable to their investments.

Tax inefficiency occurs when you don’t consider the timing of withdrawals or fail to allocate assets properly. Using a variety of tax-efficient wrappers – like ISAs, pensions, and onshore and offshore investment bonds – can shelter investments and maximise wealth management accumulation.

A smarter approach

To optimise tax efficiency, it’s essential to understand the UK tax treatment of various investment accounts:

• ISAs (Individual Savings Accounts) allow tax-free growth on your investments.
• Pensions like SIPPs (Self-Invested Personal Pensions) offer tax relief on contributions.

Other strategies include tax-efficient asset placement – use your ISA allowance for stocks and shares, rather than cash, to place higher-growth assets in tax-advantaged accounts. Many DIY investors aren’t aware of these strategies, so working with an independent financial adviser can ensure you’re doing what you can to maximise your financial outcome.

The bottom line

For investors in Cirencester and the Cotswolds, DIY investing offers great potential but comes with risks. Many DIY investors fall victim to emotional decisions or overlook important risk management strategies. These mistakes can derail long-term success.

The key to success? Managing your emotions, diversifying your portfolio, and staying focused on your goals. And if you’re unsure about something, don’t hesitate to consult an expert.

Working with an independent financial adviser, like Abode Financial Planning in Cirencester and the Cotswolds, ensures your strategy is structured to meet your long-term goals while minimising unnecessary risks.

Why local financial advice in Cirencester and the Cotswolds matters: personalised guidance from Abode Financial Planning

Join the many satisfied clients in the Cotswolds who trust Abode Financial Planning for their financial planning needs. Whether you need pension advice, investment strategies, or tax-efficient planning, we’re here to provide expert guidance.