Apple and Google are among the companies accused of conspiring not to hire away each other's employees.
As part of its settlement with the Federal Trade Commission, T-Mobile will pay at least $90 million in customer refunds, as well as penalties and fines over complaints that it put bogus charges on customer bills.
After three previous settlement attempts, regulators say formal objections are the "logical next step" if the two sides can't come to an agreement.
After a district court judge rejected a $324.5 million settlement in August, the tech firms are hoping the Ninth Circuit will intervene.
US District Court Judge Denise Cote originally took issue with the settlement because Apple could end up only paying $70 million.
After the tech giant agrees to pay millions in the e-book price-fixing lawsuit, the presiding judge says, "I'm concerned about the terms of the settlement."
After reaching a controversial deal with European regulators in February, the EU may revise terms of Google's settlement.
Court documents reveal the settlement terms for the lawsuit involving several tech giants accused of fixing wages.
The phone company hands millions to the US government in the largest-ever settlement over the opt-out-of-telemarketing registry.
A programmer who is part of the class action lawsuit against several tech giants says $324 million isn't enough.