The head of Japanese supercomputing firm PEZY Computing was arrested Tuesday on suspicion of defrauding a government institution of 431 million yen (~$3.8 million). According to reports in the Japanese press, PEZY founder, president and CEO Motoaki Saito and another PEZY employee, Daisuke Suzuki, are charged with profiting from padded claims they submitted to the New Energy and Industrial Technology Development Organization (NEDO).

PEZY, which stands for Peta, Exa, Zetta, Yotta, designed the manycore processors for “Gyoukou” one of the world’s fastest and most energy-efficient supercomputers. Installed at Japan Agency for Marine-Earth Science and Technology, Gyoukou achieved a fourth-place ranking on the November 2017 Top500 list with 19.14 petaflops of Linpack performance. Four of the five top systems on current Green500 listing are PEZY based, including Gyoukou in fifth position and the number one machine, Shoubu system B, operated by RIKEN.

Saito is also the founder and CEO of ExaScaler, which manufacturers the PEZY systems using its immersion liquid cooling technology, and Ultra Memory, Inc., a startup working on 3D multi-layer memory technology.

All three companies (PEZY, Exascaler, and Ultra Memory) have been in joint collaboration to develop an exascale supercomputer in the 2019 timeframe.

PEZY Computing was founded in January 2010 and introduced its first generation manycore microprocessor PEZY-1 in 2012; PEZY-SC followed in 2014. The third-generation chip, PEZY-SC2, was released in early 2017. The company has an estimated market cap of 940 million yen ($8.4 million).

NEDO is one of the largest public R&D management organizations in Japan, promoting the development and introduction of industrial and energy technologies.