While the FTSE 100 is struggling to make headway amid inflation fears, Wall Street's S&P500 index of high US shares is flying.

The index crashed 20 p.c in 2022, as battle in Ukraine, rising rates of interest and Chinese Covid lockdowns swamped the worldwide economic system.

Yet now it's officially in a bull market after rising by the identical proportion since early October.

The S&P500 is simply 10 p.c beneath its all-time excessive of 4,796.56, which it hit in January 2022, and buyers are hoping for extra development to come back.

In distinction to the UK, inflation is falling sharply within the US, and the Federal Reserve is anticipated to carry rates of interest at 5.25 p.c at its subsequent assembly on June 14.

If US rates of interest peak and the nation's economic system avoids a recession, issues may get even higher for shares.

By distinction, the error-riddled Bank of England may be forced to hike rates to six percent as inflation is uncontrolled over right here.

Yet a more in-depth have a look at this yr's dazzling US fairness efficiency reveals a shocking development.

Just six big-name shares are chargeable for right now's development and so they’re all within the expertise sector, says AJ Bell’s funding director Russ Mould.

“Alphabet, Amazon, Apple, Facebook-owner Meta Platforms, Microsoft and chip maker Nvidia have generated 88 percent of the S&P 500’s $3.8trillion £3trillion) gain in total market capitalisation in 2023.”

Mould warns that the market is counting on a worryingly tiny choice of shares and that's "usually a bad sign, not a good one”.

Together, they’re worth almost $10trillion and they’re starting to look very expensive amid the hype.

These six tech companies are forecast to earn a massive $295billion in 2023 but if they fall even slightly short their shares could stumble, Mould warns.

That isn't deterring UK-based pension and Isa investors from piling into technology funds that target US tech.

Investor confidence in the US has been boosted by tech-fuelled stock market rally, says Emma Wall, head of investment analysis and research at Hargreaves Lansdown.

Confidence has also risen in Japan’s stock market, which has just hit a 30-year high.

Nothing boosts investor confidence like market returns, Wall said, as investors like to dive into an asset class while it’s hot.

US tech stock Nvidia has boomed thanks to the hype surroundind artificial intelligence (AI) and machine-learning technology, as it makes the graphic processing units (GPUs) needed to drive the revolution.

Nvidia's shares are up a staggering 186.57 percent so far this year and it now has a market capitalisation of a staggering $1trillion.

It’s now part of the trillion-dollar stock club alongside US tech titans Apple, Microsoft, Google-owner Alphabet and Amazon.

Facebook-owner Meta has rebounded strongly after flopping last year and is up 117.51 percent this year.

Elon Musk’s electric car maker Tesla has also swung back into favour, rising 139.32 percent.

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Investors are snapping up tech funds and trusts to get a piece of the action. “Among the most bought funds in recent weeks are tech-heavy Baillie Gifford American and Legal & General US Index," Wall mentioned.

They are additionally snapping up specialist tech funds reminiscent of Legal & General Global Technology Index and Liontrust Global Technology. 

Allianz Technology Trust and Polar Capital Technology Trust funding trusts are additionally in demand, Wall added.

Tech shares could also be booming however buyers are cautious of nearly in all places else on the earth, aside from Japan.

Investor confidence has plunged in Asia-Pacific, Europe, rising markets and the UK, Hargreaves Lansdown figures present.

While the tech resurgence is thrilling, non-public buyers have a monitor document of diving into pink scorching funding tendencies a bit too late.

Anybody who buys tech shares now anticipating the second half of the yr to be as profitable is prone to be disillusioned.

"Past performance is never a reliable guide to the future," warns Victoria Scholar, head of funding at Interactive Investor.

Today's tech momentum might show onerous to take care of as valuations within the sector get costly.

While no pension or Isa investor can afford to shun the US inventory market, they need to approach today's extreme market with extreme caution.