The buyout firm headed by Robert F. Smith — the billionaire who stunned Morehouse College graduates this spring by telling them he would pay off all their student debt — has been slapped with an explosive lawsuit that accuses it of self-dealing.

Smith’s fund Vista Equity Partners used automotive software firm Solera Holdings as a “personal piggy bank” to bail out the fund’s flopped investments in other companies, according to the suit.

The legal salvo was filed in California state court this week by Kurt Lauk, a former top executive at Audi and a former adviser to German Chancellor Angela Merkel, who says he got booted from Solera’s board when he raised red flags about Vista’s alleged self-dealing.

Meanwhile, in a different legal filing this week, Solera said Lauk was removed from the board when he tried to shield company founder and former CEO Anthony Aquila after evidence came to light of alleged misconduct and abusive behavior by Aquila involving Solera employees. A lawyer for both men said the company’s claims basically amounted to a character assassination

Lauk joined Aquila “in trying to have Solera’s board sweep Aquila’s behavior under the rug,” leading to Lauk’s ouster from the board, Solera’s reply contended.

Aquila’s lawsuit alleged Solera is trying to “publicly cast aspersion” on Vista “in a fruitless attempt to bully Solera” into complying with his demands.

Smith has served as chairman of Carnegie Hall since 2016.

Earlier this month, Vista raised a record-breaking $16 billion for its new tech fund. New York’s state pension is one of his biggest investors and has committed $750 million to the new fund.

The legal salvo was filed in California state court this week by Kurt Lauk, a former top executive at Audi and a current advisor to German Chancellor Angela Merkel, who says he got booted from Solera’s board when he raised red flags about Vista’s alleged self-dealing.

Lauk’s suit claims that Solera, which was acquired by Vista in early 2016, arranged about a year later to buy Lytx, a driver-safety tech firm, for $1.1 billion. But Vista’s board reps including Smith allegedly blocked the purchase, insisting Lytx was only worth $800 million. Lytx was later valued at $1.7 billion by investors, according to the suit.

Meanwhile, the suit says Vista tried to force Solera to buy Omnitracs, a “failing” competitor to Lytx that Vista had acquired in 2013 and had been struggling to sell.

“Vista and Smith were hoping to pawn off Omnitracs on Solera by using Solera’s money to bail them out of an unsuccessful and poorly run acquisition, and bury it inside Solera’s portfolio,” the suit alleges.

Solera did not, in the end, buy Omnitracs. A source close to Vista said that Vista controlled Solera and could have forced a deal, but didn’t want to. The source also denied that Vista’s companies were underperforming.

“Vista and Smith never had a “growth” plan for Solera as represented,” the suit alleged. “Rather, Vista and Smith had the opposite goal for Solera, namely, to use it to bleed millions of dollars their direction.”

The suit goes on to accuse Vista of misleading its own investors. In the case of Solera, investors included Goldman Sachs and Koch Industries, the suit alleges.

“Smith claims neither he nor Vista has ever lost money in an investment so as to lure additional unsuspecting investors into Vista,” according to the suit.

But one of Vista’s investments, which the suit doesn’t name, generated about $50 million in cash flow when Vista bought it, only to see that figure reduced to zero after Vista acquired it, the suit alleges.

“Smith is hiding these losses and when those that know, speak up – like Dr. Lauk – Smith tries to discredit or terminate them,” the suit said.

When Lauk asked Solera’s board to investigate Vista’s “alleged illegal conduct,” Vista fired him to block the probe, according to the suit.

“Lauk is one of nine directors and he never voiced a concern about the transactions until almost a year after the transactions were dropped and Lauk was being removed for not fulfilling his fiduciary duties, including attempting to suppress the board recommendations regarding Aquila’s admitted misconduct after the investigation was concluded,” a Vista spokesperson told the Post.