The CIA actually conducted many measures to protect their asset, one of which was that a party who delivered an insider information was not prosecutable as there was no clear definition of its illegality in the law.
Although, practically speaking, the broker was assumed to be prosecuted as an accessory to the actual insider trading. That was why the CEO of Nomura was kicked out by the FSA.
However, there was a fault in this recognition as it was not clearly mentioned in the law, hence it was revised in 2014 that a broker of an insider information should be prosecuted for whatever reason. After all, there were gray areas between legal and illegal, which was arbitrarily judged by the FSA.
I had intentionally traded in the legal area, therefore there was no reason they should prosecute me. However, there were a plenty of others who were fallen into this gray area category, as the inspectors had really accessed to many transaction records. More precisely saying, they had conducted the illegal transaction from the practical point of view, but exempted later on as there was no clear definition of their illegality.
After all, the FSA lost this legal dispute and admitted any gray areas in those days were assumed to be legal. In the past, they could have handled this issue with their administrative authority, but it was not enough to shoot the CIA asset. It triggered a revision of the Financial Instruments and Exchange Act to bury a large part of the gray areas. In this course, a delivery of the insider information was categorized as an illegal activity.
This lost dispute left an unbalanced outcome, as the CEO of Nomura had been already fired by the FSA. The FSA’s arbitrary power was wrongly and irregularly executed to the certain party. As a reality, there were many people who conducted more unlawful behavior than fired employees of Nomura, though they have been intact in the industry. I knew this fact personally. All in all, the FSA was too wrong in any perspective, as they believed they could have conducted the right regulation without any legal righteousness.
There was no fairness during this process, as the CIA asset was exempted from a prosecution, basically in Japan. That was partially because the police left them intact under the name of give-and-take. It eventually created many corrupted players taking a lucrative profit for the insider information, but no way to be prosecuted.