When Song Meiling went to the United States for help at the end of 1948 and the beginning of 1949, she also rushed to deal with her private property in the United States and asked her nephew Kong Lingkan to help. But the exact number is unknown. It is reported that the "four big families" (mainly represented by Kong Xiangxi and Song Ziwen) used American aid materials and their special channels to engage in speculative activities in the United States in the 1940s. The US Treasury Department found out that they had evaded taxes by tens of millions of dollars and reported them to President Truman. A joint investigation by the US Central Intelligence Agency (CIA) and the US Treasury Department found that the illegal property of unknown origin in the United States actually reached more than $2 billion. The United States Senate and House of Representatives unanimously decided to permanently freeze the illegal property of four American families and antiques, calligraphy and paintings, jewelry and gold of unknown origin in the vaults of American banks, and to make up for tax evasion and fines.

1949, the illegal property of the Kuomintang government in the United States, which was permanently frozen by American officials, was more than $2 billion, which probably included Song Meiling's property, but the exact figure is unknown.