Under Armour paid other companies owned by founder and CEO Kevin Plank tens of millions of dollars to buy land and rent aircraft, according to a public document filed by Under Armour.

Under Armour paid more than $73 million last year to Plank' other businesses, including Sagamore Development Holdings, the Wall Street Journal first reported.

According to Under Armour's proxy report released late last week, Plank is Under Armour's largest shareholder with his total shares valued at more than $1.27 billion (as of March 2017). Plank's annual salary from Under Armour is only $26,000, but the proxy report shows that Plank's other business dealings with the company generate a lot of money.

Sagamore Development Holdings LLC, a subsidiary of Plank Industries, one of Plank's other companies, sold an office building and surrounding land to Under Armour for $70.3 million, WSJ reports. In the company's proxy report, Under Armour says a third-party audit committee determined the terms of the purchase were "reasonable and fair." Under Armour had previously been leasing the building.

Under Armour also leases aircraft from Plank Industries when Plank and other executives need to fly. The proxy report says Under Armour paid Plank Industries a total of $2.4 million to lease a jet and helicopter when needed. (Under Armour paid $6,500 an hour for the chopper, the proxy report says.)

Under Armour also negotiated corporate rate discounts to use the hotel Plank and his brother Scott Plank recently opened in Baltimore in March 2017. The corporate rates are "consistent with rates otherwise available for comparable hotels in the area," the proxy report says. The audit committee approved the terms.

Tom Geddes, chief executive of Plank Industries, told the WSJ that Sagamore Development didn't turn a profit on the sale of the land to Under Armour.

"The difference in sales and purchase price accounts for a variety of operating and site development costs incurred by Sagamore over the years of ownership, including lease termination costs," he said.

Under Armour said in a statement to WSJ that it "followed a thorough process in reviewing and negotiating the transaction, and our purchase price for the land reflected the fair market value as determined by independent advisors."

According to the proxy report, Under Armour started leasing the office building in 2014. The lease had a 10-year term beginning in 2016, but Under Armour broke the lease and bought the building and the property. Before buying the building and the land parcel, Under Armour's total lease payments to Plank's company were approximately $700,000 in 2016. Following a third party appraisal, the company determined the lease payments were at or below fair market lease rates. Plank's company did not charge Under Armour a penalty for breaking the lease, the proxy report says.

Under Armour told Business Insider that Plank lost money on the land deal. The company also said it will use the land to further develop the Under Armour headquarters, which would help the company.

After years of 20 percent revenue growth, Under Armour missed revenue projections for 2016 and the stock dropped by 30 percent. Plank also had a tough year politically after receiving backlash for praising President Trump, which hurt the stock price, too.

Revenue rose by 12 percent in 2016, which was the slowest growth in eight years.

Christopher Svezia, an analyst at Wedbush, says he believes all the personal business arrangements made between Plank and Under Armour are above board.

"It's not new," says Svezia. "It's been going on for years and it's always been highlighted in the proxy."