The Justice Department has filed an antitrust lawsuit against real estate software company RealPage, accusing it of an illegal scheme that allows landlords to coordinate to hike rental prices.

The lawsuit accuses the company of violating antitrust laws through its algorithm that landlords use to get recommended rental prices for apartments. Justice Department officials say the algorithm allows landlords to align their prices and avoid competition that would keep rents down.

“Americans should not have to pay more in rent simply because a company has found a new way to scheme with landlords to break the law,” Attorney General Merrick Garland told reporters.

In a statement, RealPage said the Justice Department’s claims were “devoid of merit and will do nothing to make housing more affordable.”

Mortgage rates ease to 15-month low

The average rate on a 30-year mortgage eased this week to its lowest level in 15 months, welcome relief for home shoppers navigating a housing market that remains out of reach for many Americans.

The rate fell to 6.46% from 6.49% last week, mortgage buyer Freddie Mac said. A year ago, the rate averaged 7.23%.

The average rate is now the lowest it’s been since mid-May last year, when it was 6.39%.

Borrowing costs on 15-year fixed-rate mortgages also fell this week, good news for homeowners seeking to refinance their home loan at a lower rate. The average rate fell to 5.62% from 5.66% last week. A year ago, it averaged 6.55%, Freddie Mac said.

“Although mortgage rates have stayed relatively flat over the past couple of weeks, softer incoming economic data suggest rates will gently slope downward through the end of the year,” said Sam Khater, Freddie Mac’s chief economist.