Judge Ellen Huvelle said that both companies can make claims of possible business damage caused by the AT&T and T-Mobile merger.
"Where private plaintiffs have successfully pleaded antitrust injury, the fact that they are defendants' competitors is no bar" to pursuing their claims, Huvelle wrote in a 44-page ruling, according to a report published by Reuters.
However, Huvelle also dismissed Sprint's claims that Sprint would be hurt in the market for wireless airwaves as well as in the market of backhaul services, which links Sprint's core network with remote service locations. AT&T's response indicated that the company is not too concerned about Sprint's claims that were upheld.
"We believe the limited, minor claims they have left are entirely without merit," said AT&T general counsel Wayne watts in a statement that was emailed to Reuters.
However, AT&T is facing an uphill battle as it will now have to fight not just the U.S. government, but also one of its rivals in separate lawsuits.