This could be quite a show.

“Bad boy” of Wall Street, Ross Mandell, kicked off his defense yesterday against allegations that he cheated investors out of $140 million through his now defunct brokerage firm Sky Capital.

Mandell’s lawyer, Jeffrey Hoffman, told The Post he hasn’t ruled out the possibility that his outspoken client will take the stand.

“It’s a possibility,” he said of Mandell, who posts clips of his tribulations on YouTube, including a pitch for a reality TV show of his life while fighting the charges.

Government prosecutors rested their case following four weeks of testimony from burned investors and ex-Sky brokers who said they cheated investors and used the money to live in the fast lane, including buying first-class flights and patronizing strip clubs.

The government’s final witness, a UK investor, ended his testimony by saying his experience with Sky was a “horror show,” calling employees there “con artists.”

“Pretty much everything I was told was a lie,” he said.

Also on trial is former Sky broker Adam Harrington, who put up a short defense by calling to the stand a former client, who said Harrington was a professional broker.

Mandell has certainly lived up to his “bad boy” reputation during the last few weeks, getting reprimanded twice for showing contempt toward the government’s case.

But Mandell wasn’t alone in behaving badly. The second time he was called out — for “smirking” — was after a government witness asked the judge to make him stop.

When that witness, an ex-Sky investor, left the courtroom later that day, he flipped Mandell’s lawyer the bird on his way out. The jury was still in the room.