Nvidia has more than halved the number of customers in Asia cleared to buy its artificial intelligence chips, according to the Financial Times, which cited three people with knowledge of the matter.

The company has built a new white list of approved regional buyers and stepped up due diligence in Singapore, Malaysia, and Japan, the three jurisdictions that have featured most often in the past two years of chip-diversion cases.

The tightened vetting excluded more than half of Nvidia’s previous customers there. Excluded firms can reapply, provided they make changes.

Nvidia did not do this out of enthusiasm. The tightening followed pressure from Washington, and it lands after a run of enforcement that has made the company’s Asian distribution network look, in retrospect, rather porous.

In March, US prosecutors charged a Supermicro co-founder and two employees over an alleged scheme to move roughly $2.5bn of Nvidia chips into China, using a South East Asian company as a proxy to route hardware from Taiwan.