A left-leaning group doesn't want to let voters forget about Vern Buchanan's yacht.

Floridians for a Fair Shake took out a half-page ad in the Tampa Bay Times July 31 offering $500 to the first person who can provide a picture of the Republican congressman's luxury boat.

According to the Sarasota Herald-Tribune, Buchanan purchased the yacht the same day he voted for the Tax Cuts and Jobs Act of 2017 — a measure which likely cut his taxes significantly. The tax bill cut the taxes of millions of Americans, but critics contend it disproportionately benefitted wealthy Americans like Buchanan, who made millions buying and selling auto dealerships before getting elected to Congress.

Read more: Rep. Vern Buchanan stands to gain bigly from tax bill

"We're on a mission to find that yacht, and we want your help," the ad from Floridians for a Fair Shake reads. "If you're the first person to spot and send us a photo of Vern's yacht, we'll send you $500!"

Floridians for a Fair Shake also set up a website, vernsyacht.com, offering readers the same deal.

A spokeswoman for Congressman Buchanan, who represents parts of Sarasota, Manatee and Hillsborough counties, did not immediately respond to a request for comment.

Buchanan will face the winner of the Democratic primary between Jan Schneider and David Shapiro in the November general election.

It's not the first time Floridians for a Fair Shake has thrown around anti-Buchanan ad money. According to the Herald-Tribue, the group also spent $603,718 on a television ad in July "attacking Buchanan on the tax bill."

According to its website, Floridians for a Fair Shake "advocates for an economy that works for everyone and ensuring access to affordable health care for all."

But it remains unclear who precisely is behind Floridians for a Fair Shake. Stephen Gaskill, a spokesman for the group, said it doesn't disclose its donors, but it has a "diverse array of funders."

Paperwork from the group lists Andrew Schulz, the general counsel of a group called the New Venture Fund as its "Custodian of Records."

New Venture Fund, which took in $318,405,056 in 2015 revenue according to influencewatch.org, says it is a "501(c)(3) public charity" that "supports innovative and effective public interest projects." At least one conservative publication has accused the group of being a pass through for dozens of dark money liberal groups.

Requests for comment from the New Venture Fund were not immediately returned, but Gaskill said the group had no relationship with Floridians for a Fair Shake.