Since 2018, the United States has been tightening its laws to prevent its rivals from buying into its sensitive sectors – blocking investments in everything from semiconductors to telecommunications. But the rules weren't always so strict. In 2016, Jeff Stein, a veteran journalist covering the US intelligence community, got a tip-off: a small insurance company that specialised in selling liability insurance to FBI and CIA agents had been sold to a Chinese entity. Someone with direct knowledge called me up and said, 'Do you know that the insurance company that insures intelligence personnel is owned by the Chinese?' he remembers. I was astonished! In 2015, the insurer, Wright USA, had been quietly purchased by Fosun Group, a private company believed to have very close connections with China's leadership. US concerns became immediately clear: Wright USA was privy to the personal details of many of America's top secret service agents and intelligence officials. No one in the US knew who might have access to that information now the insurer and its parent, Ironshore, were Chinese-owned.

Wright USA wasn't an isolated case. The BBC has exclusive early access to new data that shows how Chinese state money has been flowing into wealthy countries, buying up assets in the US, Europe, the Middle East and Australia. In the past couple of decades, China has become the world's biggest overseas investor, giving it the potential to dominate sensitive industries, secrets, and key technologies. Beijing considers the details of its foreign spending overseas – how much money it's spending and where - to be a state secret.

Fresh data reveals that four Chinese state banks provided a $1.2bn (£912m) loan, routed through the Cayman Islands, to allow Fosun to buy Wright USA. Stein's story ran in Newsweek magazine and prompted an immediate inquiry by the US Treasury’s Committee on Foreign Investment in the United States (CFIUS), ultimately resulting in the company's sale back to American ownership. High-level US intelligence sources confirm the Wright USA sale was one of the cases that led the first Trump administration to tighten its investment laws in 2018.

Since 2000, Beijing has spent $2.1 trillion outside its borders, with a roughly equal split between developing and wealthy countries. Recent research has revealed that much of this spending has been part of a larger strategy by Beijing to invest and buy assets globally. AidData highlights that while many thought Chinese money flowed mainly to developing nations, hundreds of billions have actually been directed toward the US, UK, and Germany.

China has a kind of financial system that the world has never seen, larger than the combined banking systems of the US, Europe, and Japan. This gives it unique capabilities, exerting control over state banks and directing credit efficiently. China's investments appear to align with its strategic objectives, outlined in initiatives like Made in China 2025, with plans to dominate cutting-edge industries like robotics, electric vehicles, and semiconductors.

Concerns in Western nations have been rising as investment patterns show a significant shift, with even traditionally open trade countries like the Netherlands reevaluating their approaches to Chinese investments, exemplified by debates around Chinese ownership of semiconductor firms. The global community is increasingly vigilant, and while numerous regulatory measures are in place, the complexities of such international transactions often hide significant risks that require careful scrutiny.