At the start of the year analysts predicted the Chinese stock market would boom as Beijing ended its hated Zero Covid policy while Wall Street would continue to fall after a tough 2022 when tech stocks crashed.

Yet after a positive first quarter the Chinese dragon ran out of puff and now seems on the brink of a total meltdown as its major property developers go bust.

In contrast, Wall Street has boomed as investors race to buy tech stocks again hoping to benefit from the artificial intelligence (AI) revolution.

The US Federal Reserve has repeatedly hiked interest rates to slow the economy and curb inflation but even this has failed to dampen the mood.

Chipmaker Nvidia is leading the charge with its share price rising 230 percent so far this year. Tech giants Apple, Amazon, Facebook-owner Meta, Google-owner Alphabet, Microsoft and Tesla have also been riding high.

Yet now the US seems to losing its way, as investors fret over whether it will get a hard or soft economic landing.

Trouble in the world’s two economic superpowers is the last thing the UK needs, as we will get caught in the crossfire.

2023 was supposed to be China's year. With strict Covid lockdowns ditched following public protests, its economy was expected to snap back at speed.

Growth quickly stalled while youth unemployment has officially hit 21.3 percent threatening social unrest. The real figure is almost certainly much higher.

China’s stock market crashed by a fifth last year, similar to the US, but while Wall Street has rebounded China hasn’t.

Now things could turn really nasty as China's property sector is on the brink of meltdown as developer Evergrande Group files for bankruptcy with debts of more than $300billion (£235billion).

This is in danger of spreading to the country’s £2.3trillion shadow banking sector, which is roughly the size of the entire UK economy.

Chinese premier Xi Jinping’s aggressive foreign policy is backfiring as the US retaliates with tariffs and import controls, weakening the country’s economy and making it harder to project power abroad.

Now here’s the twist. China isn't the only superpower economy on the brink. The US is, too.

The next presidential election looking like a fight between Democrat Joe Biden and Republican Donald Trump. Biden is suffering from cognitive decline while Trump could potentially be campaigning from behind bars.

Hopes of taming inflation are evaporating, said Victoria Scholar, head of investment at Interactive Investor. “The possibility of further Fed interest rate hikes remains firmly on the table.”

Russ Mould, investment director at AJ Bell, said the US has been bolstered by the country's free-market philosophy and deep pools of capital, but there’s a snag.

The economy is being propped by Biden’s Inflation Reduction Act (IRA), which is pumping more than $1trillion of stimulus into green infrastructure.

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The US national debt is now a dizzying $32trillion, with interest payments totalling $1trillion a year. 

“As the shock downgrade of America’s credit rating to AA+ from AAA in July makes clear, this is not sustainable,” Mould said.

US politicians complained about the downgrade but they're in denial. Neither the Democrats or the Republicans can be bothered tackling the debt. They'd rather just blame it on each other.

At least Chancellor Jeremy Hunt is trying to exert some fiscal discipline. US debt mountain will just grow and grow until something gives.

The country's stock market is worth roughly two-thirds of the global total. Wherever Wall Street goes our pensions and stocks and shares Isas will surely follow.

If the world’s two economic superpowers come crashing down, the UK will be buried in the rubble and there’s nothing we can do about it. We just don't have that kind of clout.