We have some exciting news to share! The Motley Fool UK has now become The Twelfth Magpie -- an independent, UK-owned company, led by our long-serving UK management team — Mark Rogers, Chris Nials and Heather Adlington. In practical terms, it’s the same team you know, now fully focused on serving our UK readers and members.

Just as importantly, our approach remains unchanged: long-term, jargon-free, and on your side. This site is our new home, and there will be extra tweaks made across the coming few days as we settle in. So if anything looks a little off, please bear with us!

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

Warren Buffett just sounded an alarm to the stock market

Last week Warren Buffett used a six-letter word that should give investors pause for thought. But is the Oracle of Omaha right?

| More on:
Warren Buffett at a Berkshire Hathaway AGM

Image source: The Motley Fool

You’re reading a free article with opinions that may differ from The Twelfth Magpie’s Premium Investing Services. Become a member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn more, and get a free 'Best Buy Now' stock!.

Warren Buffett has been worried about the stock market for some time. Indeed, the legendary conglomerate he and Charlie Munger built, Berkshire Hathaway, has been a net seller of stocks for 14 consecutive quarters.

As a result, Berkshire’s now sitting on nearly $400bn in cash!

Should you buy Rocket Lab shares today?

Before you decide, please take a moment to review this report first. Despite ongoing uncertainties from US tariffs to global conflicts, Mark Rogers and his team believe many UK shares still trade at substantial discounts, offering savvy investors plenty of potential opportunities to learn about.

That’s why this could be an ideal time to secure this valuable research – Mark’s analysts have scoured the markets to reveal 5 of his favourite long-term ‘Buys’. Please, don’t make any big decisions before seeing them.

Last weekend, the ‘Oracle of Omaha’ warned again about the current stock market. In an interview with CNBC, he said we’ve never had “people in a more gambling mood than now“. He likened today’s market to a “church with a casino attached“.

A casino! What should I do as an investor if Buffett is correct? Here are my thoughts.

Is there a casino?

Looking around the market, it’s not hard to spot the speculation that Buffett is referring to. Outside of crypto, the two most obvious areas to me are in the AI infrastructure buildout and the space sector.

When I mention the AI buildout, there are two parts to that. There are leading chipmakers like Nvidia, Micron and AMD whose profits are absolutely skyrocketing, thereby justifying much higher share prices (at least in the short-to-medium term).

On the other hand, there are smaller, more speculative stocks that have piggybacked on this powerful theme. For instance, Ceres Power (LSE:CWR) is up 949% in the FTSE 250 in just the past year!

The massive expansion of AI data centres has created a need for reliable on-site power. And because traditional power grids often can’t keep up, companies are turning to fuel cells. 

Ceres is a fuel cell technology company. In this sense then, the excitement makes sense.

However, Ceres is also unprofitable, with just £60m in revenue expected this year. This translates into a forward price-to-sales (P/S) ratio of 24.

I found this stock quite interesting last summer at 150p. However, now at 725p, I think Ceres is very much part of the casino that Buffett is talking about.

Speculative space

Space is another exciting growth market that has turned very speculative in 2026. We can see this with the extraordinary $1.75trn valuation that SpaceX is hoping to achieve this summer.

The rocket pioneer now has a division called SpaceXAI, so it combines both space and AI in one investment. Again though, this has driven most other space-related stocks to speculative levels.

Rocket Lab (NASDAQ:RKLB) is one. As a vertically integrated space company, this is the closest listed comparison to SpaceX.

Hence why the stock’s up roughly 2,431% in three years — including a 21% surge today (8 May).

Rocket Lab is growing like gangbusters. In Q1, revenue surged 63.5% to $200.3m, while the backlog of work grew to a record $2.2bn. It sold more rocket launches in Q1 than in the full year 2025!

The stock has been on my watchlist for some time. However, the forward P/S multiple is around 64, which I don’t think offers me much value. I think I’ll get the stock much cheaper in future if I’m patient.

Sticking to the church

If parts of the Nasdaq resemble a casino, then the London Stock Exchange is still a church, with a lot of value on offer. And perhaps because of my age, I much prefer visiting a quiet cathedral these days to a glittering casino.

So the UK is where I’ll focus my attention in May.

Ben McPoland has positions in Nvidia. The Motley Fool UK has recommended Advanced Micro Devices, Nvidia, and Rocket Lab. 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

Environmental technology concept.
Investing Articles

Down 37% in a month, what on earth’s going on with the Ceres Power share price?

Until recently, Ceres Power was the darling of the FTSE 250. But its share price has been tanking lately. James…

Read more »

Abstract 3d arrows with rocket
Investing Articles

Now below the offer price of $135 but with an $800 target, is it time to put more SpaceX shares in my ISA?

Eyebrows were raised last week when a US investment firm set an $800 price target for SpaceX shares. Given such…

Read more »

Young female business analyst looking at a graph chart while working from home
Investing Articles

Should I buy Netflix shares for my Stocks and Shares ISA after a 50% fall?

Edward Sheldon has had Netflix on his Stocks and Shares ISA watchlist for a while now. Is it finally time…

Read more »

Black woman using smartphone at home, watching stock charts.
Investing Articles

While SpaceX’s share price has crashed from $225 to $127, Apple stock has turned £5,000 into…

While other tech shares are tanking, Apple stock is hitting new all-time highs. Could it be worth a look for…

Read more »

DIVIDEND YIELD text written on a notebook with chart
Investing Articles

Down 73% but yielding 8%! Is this monster income stock worth considering?

Paul Summers takes a closer look at a once-popular growth play that has become a contrarian income stock. Is it…

Read more »

Group of friends talking by pool side
Investing Articles

How much would an ISA need to be worth to produce income equivalent to 2 State Pensions?

Experts say the State Pension isn’t generous enough to provide a basic standard of living in old age. James Beard…

Read more »

Chalkboard representation of risk versus reward on a pair of scales
Dividend Shares

With a 10.1% yield, is this income share a no-brainer?

Jon Smith explains why it's hard to find a high-yield income share that's very sustainable, but runs through a potential…

Read more »

many happy international football fans watching tv
Investing Articles

With a P/E ratio of 9, is this a top-notch value share to consider buying today?

On paper at least, this FTSE 250 stock appears to offer tremendous value. But investors don’t appear convinced. What’s going…

Read more »