The chipmaker's share price climbed to an all-time high on Tuesday.

The stock ended the trading day at nearly $136, that's up 3.5%.

NVIDIA of course makes computer chips needed for artificial intelligence software and demand for its products has boosted its sales and profits over the last few years.

Many investors believe its earnings can grow even more, which has caused its share price to soar, though some have questioned its sky-high valuation.

Our business reporter Surinjana Tiwari has more.

Here's a whopping number for you, 591,000%.

That's how much NVIDIA stock has increased in value since it went public in the early 2000s.

And now the chip company has surged its way all the way to the top of the stock market, dethroning another tech heavyweight, Microsoft, to become the world's most valuable company by market capitalization.

And this just weeks after NVIDIA was in third place.

It overtook iPhone maker Apple last week.

Much of this growth has happened this year alone, taking the company from a $1 trillion company to a $3 trillion company within a matter of months and lifting US stock markets to record highs in the process.

The stunning surge is all down to the optimism around emerging AI technology and the demand for high-end processors, the type of kit that NVIDIA makes chips for and that support artificial intelligence technology.

All the tech giants, Microsoft, Meta and Google owner Alphabet are all competing to build out their AI computing capabilities and add the technology to their products and services.

Now, it does seem that NVIDIA is unstoppable, but some people are concerned about the sky-high value of the company, and also they fear that the demand for AI technology and the spending around it might wane in the future.

So, they are cautious even though there is this very high valuation.

So, that was Surinjana Tiwari there.

Let's talk a little bit more about NVIDIA and what it all means.

Tom Stevenson is the Investment Director at Fidelity, and he's come back onto the programme with us.

Hello there, Tom.

There are concerns, aren't there?

I mean, some people are saying that this compares to what we saw with the dot-com bubble.

Is that a fair comparison?

To an extent, it is a fair comparison.

I mean, the scale of increase in the value of NVIDIA is really something that we haven't seen for 25 years in the stock market, just a bit of context.

The S&P 500 is up 15% so far this year.

A third of that is accounted for by just this one company.

And another bit of context, two years ago, NVIDIA was worth $300 billion in the stock market.

It's now worth 11 times as much.

Now, it's pretty remarkable for any company to grow 11-fold in two years, but when the starting point is already a very big company, it's an even more remarkable story.

So, is it justified?

I think, to an extent, it is justified.

NVIDIA's revenues and its earnings are growing very fast.

Back in February, we heard revenues were up 260%.

Then in May, we had exactly the same growth rate.

So, a remarkable growth story in earnings on the back of this excitement about AI.

And to an extent, I think that does justify the growth in the value of NVIDIA.

This has also been described as something of a chip race.

Who's in the running?

Who are the competitors and how are they doing?

Are they playing catch up with all of this?

Well, they are playing catch up.

I mean, NVIDIA really dominates this market, but it's unlikely that it's going to remain out in front indefinitely because all the other big chip makers, the Intels, the AMDs, they're all producing chips as well.

So, there will be a lot of competition in this space.

And I think if there is a question mark about NVIDIA's valuation, which stands at about 40 times earnings, that's a pretty punchy rating for any company.

I think if there is a question mark, it is about the extent to which it can remain out in front for the foreseeable future.

Tom, I wonder if you can explain something to me.

Is it that their chips are particularly good at what they do or is it that they just position themselves to be in the right place at the right time?

Well, do you know what?

I think it's a bit of both.

I mean, NVIDIA has ridden the hardware waves in the 30 years that it's been in existence.

It started out as a gaming chip company.

Its chips were in the Xboxes and the PlayStations and all of those.

But really, it's adapted with the times and it saw this opportunity in AI processing.

And it has ridden that really well.

So, yes, its chips are very good, but it's also been in the right place at the right time.

And what can you tell us about Jensen Huang?

Who is this 61-year-old who's done incredibly well for himself?

Yeah, so he was the co-founder of NVIDIA 31 years ago.

And he has done a remarkable job.

He's been the chief executive throughout that period.

And he owns 3% of NVIDIA.

He is now an extremely wealthy man.

His own personal wealth now worth over $100 billion.

And with just 3% of the company.

My goodness.

OK, Tom Stevenson, thank you very much indeed for that.

Thank you.