How do you apologize to people when you've lost all of their money, possibly $200 million or more?

If you're James Cordier, head of a Tampa hedge fund with clients all over the world, you do it in a bizarre video posted on YouTube. Alternately stone-faced and choked up, Cordier calls his clients "family'' and addresses several by name: Dr. Steve, in L.A. John in Texas. And "Jeff, "the biggest hockey fan in the world'' — Tampa Bay Lightning owner Jeff Vinik.

"The events of this past week,'' Cordier says on the Nov. 16 video, "have been incredibly devastating. This rogue wave I was unable to navigate has cost me my hedge fund. I'm sorry that the rogue wave capsized our boat.''

Cordier founded OptionSellers, named for the financial tool that gives investors the right to buy or sell stocks or commodities at a fixed price. Author of a popular book — How Selling Options Can Lead to Stellar Returns — he has been quoted in the Wall Street Journal, New York Times and other media.

In trading natural gas options for his clients this month, Cordier assumed that gas prices would drop because of a milder than expected winter. But on Nov. 14, natural gas futures shot up as much as 20 percent — the biggest gain in eight years — and wiped out all of his clients' investments.

Even worse, many in Cordier's "family'' also had retirement accounts with a New York brokerage and had borrowed money from those accounts to try to stem their option losses. Now those clients will have to pay back the brokerage.

"So they actually lost more than they had in their account" with Cordier, said Jason Albin, an Ohio lawyer. "It's been pretty unreal for them.''

Albin's firm represents investors who have suffered losses in the markets due to fraud or misconduct. Since OptionSellers collapsed, dozens of Cordier's clients have contacted the law firm from all over the United States and as far away as Malaysia, Nigeria and the United Arab Emirates.

"They all had substantial assets,'' Albin said, "and the clients really run the gamut from fairly sophisticated to no sophistication at all.''

Albin estimates that most of Cordier's 300 clients had invested at least $500,000 with OptionSellers; one invested more than $3.5 million. Based on figures the law firm has heard so far, "we're talking hundreds of millions (in losses), as in $200 million or more,'' Albin said.

The obvious target of an investors' suit would be OptionSellers.

"They were charging exorbitant fees and using extremely risky trading strategies and you can see what the aftermath was,'' Albin said. "Those are the obvious claims but they've already gone dark and may be bankrupt in a few weeks.''

No one answered the phone Friday at Cordier's firm in the SunTrust Financial Centre in downtown Tampa. Cordier, who lives in a bayfront Apollo Beach house he bought last year for $1.6 million, did not return a phone message.

A much deeper pocket is INTL FCStone, the brokerage that handled Cordier's option trades. It is a public company with nearly $30 billion in revenues last year.

FCStone "had duties and responsibilities to know their customer and vet advisors trading on their accounts and have risk procedures in place to prevent these things from happening,'' Albin said.

Many of Cordier's clients had qualified Individual Retirement Accounts at FCStone. Generally, money in such accounts is not supposed to be used for the risky type of trading that Cordier did on the clients' behalf.

"So FCStone is permitting this, and now (the clients) have FCStone demanding payment,'' Albin said. "People can't even stop for a second to process what happened, they also have to frantically figure out how they are going to liquidate other assets.''

In his YouTube apology, which Bloomberg News likened to a "hostage video,'' the 56-year-old Cordier is seated at a desk against a nearly black background. He is wearing a dark suit, white shirt with cuff links and what appears to be a Rolex watch.

Cordier, talking slowly, either looks directly at the camera or turns his eyes down, as though trying to compose himself. He rues that he won't be able to join one client on the Riviera or watch a "golden sunset'' in Australia with another.

In speaking to "Jeff, the world's biggest hockey fan,'' Cordier says: "You know who you are. All I want to do with you is sit and watch a game. Next time I'm at the arena, I know you'll be there and I'll pretend I'm sitting next to you.''

Through a spokesperson, Vinik confirmed he was among Cordier's clients but made no further comment.

Albin, the Ohio lawyer, said he can't bring himself to watch the entire video, which runs about 10 minutes.

"It makes me too aggravated,'' he said. "He's crying and whining about all the money he's lost investors but it's not going to put money back in their pockets.''

Contact Susan Taylor Martin at smartin@tampabay.com or (727) 893-8642. Follow @susanskate.