Bangladesh, Sept. 16 -- The most revealing part of the Huawei story may not be what happened inside a courtroom in New York. It may be what happened one Saturday morning in London, thousands of miles away, when nine bankers were summoned to work before sunrise to move $1.3 billion belonging to a major Chinese technology company.

The transaction itself was not illegal. But the circumstances surrounding it raise a far more consequential question: when the interests of a powerful Chinese company collide with the compliance rules of a Western financial center, whose interests ultimately prevail?

According to confidential records reviewed by the International Consortium of Investigative Journalists (ICIJ), the answer in this case appeared in...