• Sports gambling giant DraftKings apologized for a bet parlay offer that would have paid out if three New York teams won on the 22nd anniversary of the Sept. 11 terror attacks.
• The vast majority of 9/11 deaths occurred in the World Trade Center's Twin Towers in lower Manhattan, and aboard the two commercial airline jets that struck them.
• To win the parlay, the New York Yankees and Mets baseball teams, and the New York Jets football team, needed to win.

Sports gambling giant DraftKings apologized Monday for a bet parlay offer that would have paid out if three New York teams won on the 22nd anniversary of the Sept. 11 terror attacks that killed almost 3,000 Americans.

The vast majority of 9/11 deaths occurred in the World Trade Center's Twin Towers in lower Manhattan, and aboard the two commercial airline jets that struck and destroyed them.

The parlay DraftKings was touting earlier Monday said, "Never Forget," a term frequently applied to the Sept. 11 attacks.

"We sincerely apologize for the featured parlay that was shared briefly in commemoration of 9/11," DraftKings said on X, the social media site formerly known as Twitter.

"We respect the significance of this day for our country and especially for the families of those who were directly affected," the company said.

The parlay would have paid out if the New York Yankees, Mets and Jets won Monday.

The offer elicited fierce criticism on social media before it was yanked by the company.

"Absolute clowns," one X user wrote in reply to DraftKing's apologetic tweet.

"Shameful," another user wrote.

"No, you do not respect the significance of the day, nor do you respect the human beings who bet on sports with you," read another post.

Bret Eagleson, whose father, Bruce, was killed at the Trade Center told The Associated Press, "It is shameful to use the national tragedy of 9/11 to promote a business.

"We need accountability, justice and closure, not self-interest and shameless promotion," said Eagelson, who operates a group called 9/11 Justice.

More than 30 states and the District of Columbia have launched legal betting markets since a landmark 2018 U.S. Supreme Court case paved the way for any state to offer legal sports wagering.

For 2023, the market is projected to top $7.6 billion, according to Statista Market Insights.

Ten years ago, AT&T deleted a tweet that featured a hand holding a mobile phone capturing an image of the Tributes in Light, which are two beams of light projected up from lower Manhattan showing where the Twin Towers once stood. The tweet said, "Never Forget."

"We apologize to anyone who felt our post was in poor taste," AT&T said in a subsequent tweet. "The image was solely meant to pay respect to those affected by the 9/11 tragedy."

— Additional reporting by CNBC's Stefan Sykes