A billionaire co-owner of the San Francisco Giants gave money to a political action committee behind a racist radio ad in Arkansas that features two women saying Democrats could bring back lynchings if black voters don’t support the GOP.

Charles B. Johnson, who is believed to own the largest stake in the Giants, gave $1,000 this summer to Black Americans for the President’s Agenda, a super PAC that supports President Trump’s policies and conservative candidates, according to the group’s financial disclosures.

On Friday, Johnson, a frequent contributor to conservative groups and candidates, released a statement saying he didn’t know his donation would be used for the ad.

“I had absolutely no knowledge that this donation would be used in this manner and I, like the Giants organization, strongly condemn any form of racism and in no way condone the advertisement that was created by this entity,” Johnson said.

Released just ahead of the midterm elections, the radio ad features a conversation between two women, whom the ad implies are African Americans. The two women encourage black voters in Arkansas to support Rep. French Hill in his re-election bid against Democrat Clarke Tucker.

Hill, a Republican, called the ad “race-baiting” and thousands of people have shared their outrage on social media. In the commercial, the two women focus their conversation on the sexual misconduct allegations against Supreme Court Justice Brett Kavanaugh.

“Our congressman, French Hill, and the Republicans know that it’s dangerous to change the presumption of innocence to a presumption of guilt, especially for black men,” one woman says.

Another woman responds, “White Democrats will be lynching black folk again.”

She then says, “We can’t afford to let white Democrats take us back to bad old days of race verdicts, life sentences and lynchings when a white girl screams rape.”

The Giants released their own statement Friday calling the ad “disturbing and divisive political activity.”

“The Giants’ reputation as one of the most inclusive and socially engaged professional sports teams in the nation speaks for itself,” the organization said. “We are unaware of Mr. Johnson’s political donations because they are entirely separate from his stake in the Giants ownership group.”

Hill, who represents the Second District, which is 23 percent black, called the ad “appalling” on Twitter after its release.

“I condemn this outrageous ad in the strongest terms,” Hill tweeted. “I do not support that message, and there is no place in Arkansas for this nonsense.”

His opponent, Tucker, said the commercial is “disgraceful and has no place in our society.”

Vernon Robinson, co-founder and treasurer of the super PAC that created the ad, said that before it aired he sent Johnson a letter detailing his plan to encourage black people to support the GOP.

“I assume he thought (the letter) was good enough to send a check,” Robinson said of Johnson’s contribution.

The ad cost $50,000, said Robinson, who added that he has no plan to remove it from the air. Instead, he plans to air more ads in Kansas City and St. Louis — or what he called “the two urban areas in Missouri.”

In addition, Robinson announced plans to distribute booklets detailing the Democratic Party’s “heinous crimes.” He also said he will train military officers and sergeants to be community organizers who will work in the swing states, or “the soft underbelly of the Democratic Party.”

Democrats “are going to walk the plank in Arkansas and Missouri,” Robinson added.

Johnson is a registered Republican who owns property in Hillsborough.

He has a net worth of $5 billion and is the largest shareholder in Franklin Resources, a global investment management firm started by his father, according to Forbes. In 1957, Johnson became CEO at the age of 24. The firm’s assets grew from $2.5 million to more than $800 billion in 2013, when he retired and handed over the leadership role to his son.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani