Current President Hisao Tanaka and his predecessor are both expected to resign over the profit-padding scandal after investigators uncovered irregularities stretching back to 2008.
The panel, headed by a former Tokyo prosecutor, painted the picture of a corporate culture where underlings could not challenge powerful bosses who were intent on boosting profits at almost any cost.
"Inappropriate accounting was systematically carried out as a result of management decisions... Betraying the trust of many stakeholders," according to a summary of the report released by the firm.
Toshiba's accounting scandal, one of the most damaging to hit Japan in recent years, began when securities regulators uncovered irregularities as they probed the company's balance sheet earlier this year.
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"In some cases top management and division leaders appeared to have shared a common objective to inflate profits," the panel said.
Best known for its televisions and electronics, including the world's first laptop personal computer and DVD player, Toshiba has more than 200,000 employees globally and also operates in power transmission and medical equipment.
Among the divisions affected by the inflated profits are the infrastructure, audio-visual and semiconductor businesses, the summary said.