About
About Invest in ETFs
A plain-English guide to investing for people in the UK who have never done it. No jargon, and nobody trying to sell you anything.
Invest in ETFs explains what exchange-traded funds are, how they work and how to get started. Every guide starts with the short version, then shows the evidence.
Who writes it
I’m Sam Pybis, an economist. By day I’m a Senior Lecturer (Associate Professor) in Economics at a UK university. My research is in empirical finance and asks when, and why, stock market returns can be forecast.
All my degrees are from the University of Liverpool, from a first-class degree in Economics to a PhD on forecasting stock market returns. I’ve also written for The Conversation on why Britons are less likely than Americans to invest in stocks.
This site is what I do off duty. I write it in my own time, for people rather than for other economists, and the guides carry my pen name, The Off-Duty Economist.
The site isn’t connected to my university, and nothing here is written, reviewed or approved by my employer. The views are my own.
My research, publications and CV are on my personal website, and you can also find me on LinkedIn.
Education
- PhD Economics and Finance2017–2022
University of Liverpool
Thesis: “Three Essays Exploring Predictive Regressions”. ESRC-funded. Predictive regression frameworks for asset returns, focusing on persistence, model evaluation and real-time forecasting.
- Masters in Finance (Distinction)2015–2016
University of Liverpool
Financial econometrics, portfolio construction and asset pricing.
- Undergraduate in Economics (First Class)2012–2015
University of Liverpool
Including an international exchange at the University of Georgia, USA.
Why this site exists
Studying economics and finance, I kept having the same thought: much of what I was being taught should be common knowledge, not something you only learn at university. None of it is secret. It just isn’t explained anywhere in plain English, by someone with nothing to sell.
I’m passionate about explaining how investing works: the mechanics. What an ETF is and what it costs. How an ISA or a pension works. How compounding works, and what really happens in a crash. I won’t tell you what to invest in. That depends on your circumstances, and that’s what regulated advisers are for. But how investing works should be known by everyone.
Right now it isn’t. More than half of UK adults with significant cash savings and no investments say they haven’t considered investing. When the FCA asked why, the top reasons were fear of losing money and not knowing enough to start. Both are fair. Investing does carry risk, and much of what’s written about it is either baffling or trying to sell you something. This site deals with the second problem, so you can weigh up the first one properly.
Investing isn't just for the wealthy any more
For a long time, investing felt like something for wealthier people. You went through a stockbroker or a fund manager, and the fees took the biggest bite out of small sums.
ETFs and index funds changed that. A large global or UK index ETF can now cost between 0.07% and 0.20% a year, many platforms let you start with small regular amounts, and a single ETF can spread your money across hundreds or even thousands of companies.
So I think investing is worth considering for most people, even if it’s only a small amount, once they have an emergency fund in cash and no expensive debt.
Compounding is everything
Compounding means your returns start earning returns of their own. It’s slow at first and powerful later, which is why time matters more than almost anything else. As an illustration, here’s what regular saving would grow to if money grew by a steady 5% or 10% a year:
| If you save | You pay in | At 5% a year | At 10% a year |
|---|---|---|---|
| £100 a month for 40 years | £48,000 | about £148,000 | about £555,000 |
| £100 a month for 30 years | £36,000 | about £82,000 | about £206,000 |
| £150 a month for 15 years | £27,000 | about £40,000 | about £60,000 |
Starting ten years earlier, with only £12,000 more paid in, ends with about £67,000 more at 5% a year, or about £349,000 more at 10%. That’s the case for starting early. But the last example matters too: it’s never too late, and money invested at 50 still has years to grow.
The 10% is roughly what the US S&P 500 returned a year, on average, from 1928 to 2025, with dividends reinvested and before inflation. The 5% is a more cautious figure. Neither is a promise: real returns go up and down from year to year, charges and inflation reduce them, and no investment guarantees any return.
A century of crashes, and growth anyway
The S&P 500, the index of 500 large American companies, is a good example. In historical data compiled by Professor Aswath Damodaran of NYU Stern, $100 invested at the start of 1928, with dividends reinvested, grew to about $1.16 million by the end of 2025. That’s more than 11,000 times the starting amount: about 10% a year over 98 years, before inflation, costs and tax.
That figure includes every crash along the way. Measured from the end of one year to the end of another, with dividends reinvested:
- The Wall Street Crash: down about 65% between the end of 1928 and the end of 1932, and not back above its old level until 1936.
- The 1970s oil crisis: down about 37% over 1973 and 1974.
- Black Monday, 1987: the Dow Jones index fell 22.6% in a single day on 19 October. The S&P 500 still ended the year up about 6%.
- The dot-com crash: down about 37% from 2000 to 2002, and not back above its old level until 2006.
- The global financial crisis: down about 37% in 2008 alone.
- Covid: despite the crash in early 2020, the index ended that year up 18%.
None of this is a promise about the future. Past performance is not a reliable guide to future returns, the S&P 500 is one country’s market, and recoveries can take years. The figures are in US dollars, so a UK investor’s return would also depend on the exchange rate. Every big UK crash since 1871 shows the same pattern in UK shares, including how long each recovery took.
Your pension, your choice
Pensions have changed too. Since 6 April 2015, people aged 55 or over have been able to take as much of their defined contribution pension as they wish, without having to buy an annuity. That’s years before State Pension age. The minimum age rises to 57 on 6 April 2028.
You also have more say over how your pension is invested. A self-invested personal pension (SIPP) lets you choose your own investments, including low-cost index funds and ETFs: ETFs in a SIPP explains how. Charges have come down as well. Since April 2015, the default fund of a workplace pension used for automatic enrolment has been capped at 0.75% a year, and a large index ETF can cost a fraction of that.
Two warnings. Taking pension money before the minimum age usually means tax of up to 55%, and companies offering early access are a known trap. And moving an old pension isn’t always wise: check for exit fees and valuable guarantees first. If a defined benefit (final salary) pension is worth over £30,000, you must get financial advice before you’re allowed to transfer it. If you’re 50 or over, Pension Wise offers free, impartial guidance.
That’s why this site exists: to explain the mechanics clearly, with the evidence, so you can make your own decisions with confidence. ETFs are a sensible place to start. They’re simple, they’re usually cheap, and they’re a good way to see how all of this works in practice.
What you'll find here
- ETF basics: what an ETF is, what it costs and how safe it is
- Getting started: stocks and shares ISAs, SIPPs, platforms and buying your first ETF
- Worries and myths: what really happens in a crash, and what inflation does to cash
- What the research says: plain-English summaries of the academic evidence
- Tools and data: calculators and charts built from public data
What you won't find here
- Ads, affiliate links or sponsored posts
- “Best ETFs to buy” lists or share tips
- Recommendations about what you personally should do
How I work
- Every factual claim links to its source: GOV.UK, HMRC, the FCA, fund documents or published research.
- Every page shows when it was last reviewed. Tax allowances and limits are rechecked each April, when they change.
- When I get something wrong, I correct it and log the change on the corrections page.
- No fund provider, platform or bank pays me or this site anything.
The full detail is in the editorial policy.
Education, not advice
This site explains how investing works. It can’t tell you what’s right for you, because it doesn’t know your circumstances.
The value of investments can go down as well as up, and you may get back less than you put in.
For free, impartial guidance, try MoneyHelper, the government-backed service. For advice on your own situation, use a regulated financial adviser, and check them on the FCA register first.
Please read the full disclaimer before acting on anything on this site.
How the site is funded
It isn’t. There are no ads and no affiliate links, and I cover the running costs myself. If that ever changes, this page will say so first.
Get in touch
Spotted a mistake, or have a question you’d like answered on the site? Use the contact page. I read everything, though I can’t give personal advice.