Republican front-runner Donald Trump is facing multiple class action lawsuits for fraud because of his online education venture called The Trump Entrepreneur Initiative, commonly known as Trump University.

What is Trump University?

Trump University was first founded by The Trump Organization in early 2005, but the name changed to The Trump Entrepreneur Initiative in June 2010 after critics accused the name of being misleading.

The company, entirely an online entity, offered courses in real estate, asset management, entrepreneurship and wealth creation. Depending on the program, tuition fees ranged from $1,500 to $35,000.

The organization was never accredited and participants never received college credit. In 2011, operations were largely halted after several participants called the online courses a scam.

When did the lawsuits emerge?

The state of New York filed a $40 million civil suit against Trump University for alleged illegal business practices and marketing false claims. Trump himself denied the allegations but was found guilty by a New York judge in 2014 for operating the organization without a proper business license.

Despite finding Trump personally liable, the judge said the statute of limitations prevented lawyers from seeking compensation for the victims of the scam. The primary lawyer appealed the decision and won, but it is not yet clear whether the fake university defrauded students and whether Trump will have to pay damages.

A separate suit was filed in early 2014. A federal judge in San Diego allowed accusations by litigants in the states of California, Florida and New York to continue. There are an estimated 5,000 victims of the organization nationwide with claims dating back to 2007.

Former Trump University student Tarla Makaeff spent around $37,000 on classes and joined one of the class action lawsuits. She used social media to publicize her experiences. Shortly thereafter, Trump filed a defamation lawsuit against Makaeff for $1 million but was unable to prove malice. In early 2015, he was ordered to pay Makaeff and her lawyers legal fees and costs amounting to $798,774.

Though Trump has claimed he won all lawsuits against Trump University, three cases were still pending as of last month.

How has this affected Trump’s campaign?

The topic of the Trump University controversy and lawsuits was brought up at the March 3 Republican debate in Detroit by Fox News reporter Megyn Kelly.

When addressing the lawsuits in court and on the campaign trail, Trump has repeatedly denied the allegations and said the lawsuits have no merit. He continues to assert he has either won the cases or will win them in the near future.

His rivals in both parties have tried to use the Trump University fraud allegations against him as proof that he is a con artist. But Trump continues to do well in national polls and state primaries. Trump has continued to argue the allegations are ungrounded. Though the Trump University controversy is still underway, it has appeared to have little to no effect on Trump’s base of support among Republican voters.