Hi,
His illegal stock manipulations led to his jail sentence.
"Stock' refers to the public ownership of a company. Capitalists buy and sell stocks.
'Manipulation' means handling something.
'Stock manipulation' refers to a process in which someone changes the price of a stock via an illegal act. eg Company X is very unsuccessful but I tell lies to make it sound successful, in order to make people want to buy my stock in the company. This kind of thing happens quite often.
Bets wishes, Clive