Share your opinion and earn yourself a free Motley Fool premium report!

We are looking for Fools to join a 75 minute online independent market research forum on 15th / 16th December.

To find out more and express your interest please click here

Here’s the secret behind my best-ever investment on the stock market

Dr James Fox explains why he made what’s now his most successful investment on the stock market. It’s a simple model for investors to try.

| More on:
Businessman with tablet, waiting at the train station platform

Image source: Getty Images

You’re reading a free article with opinions that may differ from The Motley Fool’s Premium Investing Services. Become a Motley Fool member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn More.

Investing in the stock market can be daunting. Investors often don’t know where to start. However, even without subscriptions to data and analytics companies, they can typically access some fairly thorough earnings and valuation data. These numbers should provide the basis for any share purchase.

Currently, my most successful investment ever is in US software company AppLovin (NASDAQ:APP). The company’s up around 1,500% from my first buy and actually remains one of my daughter’s largest holdings. So, what made it such a great pick?

The value proposition

I bought shares in AppLovin for the first time around two years ago. According to my notes, the stock was trading around 43 times earnings from the previous 12 months but just 14 times earnings for the forward year.

This pointed towards the company’s impressive growth trajectory. Earnings growth was projected at 150% and evidence suggested this wasn’t a one-off or just a good year.

Unsurprisingly, it was about artificial intelligence (AI). The company had just released a new AI model that made app monetisation much more effective — it didn’t open the apps but provided the software for development, advertising and monetisation.

This resulted in a forward earnings per share growth rate that was around 45%. In other words, analysts expected earnings to increase by this much annually over the medium term. The price-to-earnings-to-growth ratio was around 0.5, indicating severely undervalued conditions.

Hold your winners

I’ve not always been the best at holding my winners. I remember selling BAE Systems shares before Russia invaded Ukraine and pocketing a 30% gain. If I’d held, I’d now be up 400%.

But I’ve held AppLovin through multiple earnings cycles and it just keeps smashing analysts expectations. Momentum has been great and analysts were constantly having to revise their expectations upwards — this is always a great sign.

However, there sometimes comes a point when you have to question the valuation. Once again, the numbers are the most important thing. Because investing is about making probability-weighted decisions.

Today, AppLovin trades at 55 times forward earnings but the average medium-term earnings growth rate is 20%. This gives us a PEG ratio of 2.8. That’s nearly six times higher than when I bought the stock.

To me, this suggests, on a probability-weighted basis, that the stock won’t go much higher. I absolutely could be wrong because AI stocks still have a lot of momentum, but the data tells me it’s at or above fair value.

Lessons learned

I don’t expect to hold AppLovin in the family portfolios I manage for much longer. However, I do hope to put this money to good use as I go forward by applying the same model. The stock market might be a little hot, but there’s certainly more companies to buy today with similar growth prospects and better valuations. And for the record, I don’t believe AppLovin is worth considering today.

James Fox has positions in AppLovin. The Motley Fool UK has recommended BAE Systems. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

Light trails from traffic moving down The Mound in central Edinburgh, Scotland during December
Investing Articles

Start investing this month for £5 a day? Here’s how!

Is a fiver a day enough to start investing in the stock market? Yes it is -- and our writer…

Read more »

Young mixed-race couple sat on the beach looking out over the sea
Investing Articles

Investing in high-yield dividend stocks isn’t the only way to compound returns in an ISA or SIPP and build wealth

Generous payouts from dividend stocks can be appealing. But another strategy can offer higher returns over the long run, says…

Read more »

Middle-aged white man wearing glasses, staring into space over the top of his laptop in a coffee shop
Investing Articles

A rare buying opportunity for a defensive FTSE 100 company?

A FTSE 100 stock just fell 5% in a day without anything changing in the underlying business. Is this the…

Read more »

Two elderly people relaxing in the summer sunshine Box Hill near Dorking Surrey England
Investing Articles

Simplify your investing life with this one key tip from Warren Buffett

Making moves in the stock market can be complicated. But as Warren Buffett points out, if you don’t want it…

Read more »

Tesco employee helping female customer
Investing Articles

Is Tesco a second income gem after its 12.9% dividend boost?

As a shareholder, our writer was happy to see Tesco raise dividends -- again. Is it finally a serious contender…

Read more »

Rolls-Royce Hydrogen Test Rig at Loughborough University
Investing Articles

Has the Rolls-Royce share price gone too far?

Stephen Wright breaks out the valuation models to see whether the Rolls-Royce share price might still be a bargain, even…

Read more »

Tŵr Mawr lighthouse (meaning "great tower" in Welsh), on Ynys Llanddwyn on Anglesey, Wales, marks the western entrance to the Menai Strait.
Investing Articles

How much do you need to invest in a FTSE 100 ETF for £1,000 monthly passive income?

Andrew Mackie tested whether a FTSE 100 ETF portfolio could deliver £1,000 a month in passive income – the results…

Read more »

Two business people sitting at cafe working on new project using laptop. Young businesswoman taking notes and businessman working on laptop computer.
Investing Articles

One of my top passive income stocks to consider for 2026 is…

This under-the-radar income stock has grown its dividend by over 370% in the last five years! And it might just…

Read more »