Matt Dunham/Associated Press

The projected cost of the Los Angeles Rams' new stadium in Inglewood, California, which is scheduled to open in 2020, has reportedly exceeded $4 billion.

On Monday, Daniel Kaplan of the Sports Business Journal reported the investment by Rams owner Stan Kroenke and wife Ann Walton Kroenke is more than double the next highest amount paid for an American athletic venue ($1.7 billion for MetLife Stadium in East Rutherford, New Jersey).

Reasons for the increased costs include access roads, utilities and making sure the stadium could withstand an earthquake, per Kaplan. The final total could approach $5 billion when the new NFL Network building is factored into the equation.

Los Angeles Stadium at Hollywood Park is also expected to house the Los Angeles Chargers, though the Rams are the primary equity partner in the high-priced facility.

Kroenke, who Forbes estimates to have an $8.3 billion net worth, said in January he lamented the Rams' lack of home-field advantage in their temporary home, the Los Angeles Memorial Coliseum.

"In two years we'll be in a new stadium, and I think we can have a true home-field advantage like a lot of the teams do," Kroenke told Josh Peter of USA Today. "We don't really have it now."

The Rams finished 26th in the NFL in average attendance (63,392) in 2017, per ESPN.com. The Chargers, who are playing at the StubHub Center, ranked last (25,335).

The new stadium is going to feature a 70,240 capacity expandable to over 100,000 for major events.