The Chinese government poured billions into chip projects last year which stalled or failed and now apparently it wants to know what happened to the money.
In a statement, the Central Commission for Discipline Inspection, which sounds like a dominatrix rather than a fraud watchdog said that Zhao "took the state-owned company he managed as his private fiefdom."
The regulator says he handed profitable businesses to his relatives and friends, and purchased goods and services from companies managed by his associates at "prices significantly higher than the market".
Zhao's case, it adds, has been handed to prosecutors who will file charges against him.
Tsinghua Unigroup was once a branch of the prestigious Tsinghua University, attended by President Xi Jinping.
It racked up debt under Zhao's leadership and defaulted on several bond payments in 2020. It completed a 20-month restructuring last July. This placed it under the control of a consortium led by two state-backed venture capital firms.
Zhao stepped down as the chairman and Chinese media outlets reported that he had been taken from his home by authorities for investigation.
He is not the only one. Several leading figures in the Chinese semiconductor industry have been placed under investigation.