For a while there it looked like Hong Kong was going to supplant China and Japan in the US Treasuries ownership stakes. The SCMP:

Forged US treasury bonds with a face value of US$250 billion have been seized in the biggest police operation of its kind for more than two years. Four Taiwanese people will appear in Kowloon City Court tomorrow charged with possession of false instruments.

Police said yesterday that the case came to light when a 79-year-old man contacted them earlier this month, saying he had been approached by one of the accused and asked for help in trading two boxes of US treasury bonds with a face value of US$500 million each. Officers of the Commercial Crime Bureau took over the case and arranged a meeting with the Taiwanese at a guesthouse in Jordan on Thursday, with officers posing as prospective buyers.

Three men and a woman, aged between 30 and 65, were arrested when two boxes each containing 250 suspected forged US treasury bonds were seized. A quantity of other suspected false instruments, including photographs and scanned images of foreign currency notes and bank and business documents, were also found during the operation... in February 2003, 16 boxes containing 4,000 items of forged US treasury bonds with a face value of US$2 trillion were seized from a flat in Central as part of an operation against an international fraud syndicate.

Two years earlier, two men, an Australian, 77, and a Briton, 58, were arrested over the seizure of forged US treasury bonds with a face value of US$490 million in a bank in Central. This subsequently led to the discovery of 44 boxes of similar suspected forged US treasury bonds in a bank in London.