National Basketball Association players rejected the league's latest offer Monday and have begun the process to disband the union.
The decision likely jeopardizes the season.
"We're prepared to file this antitrust action against the NBA," union executive director Billy Hunter said. "That's the best situation where players can get their due process."
He said players were not prepared to accept NBA Commissioner David Stern's ultimatum, saying they thought it was "extremely unfair."
"This is the best decision for the players," union president Derek Fisher said. "I want to reiterate that point, that a lot of individual players have a lot of things personally at stake in terms of their careers and where they stand. And right now they feel it's important — we all feel it's important to all our players, not just the ones in this room, but our entire group — that we not only try to get a deal done for today but for the body of NBA players that will come into this league over the next decade and beyond."
Fisher, flanked at a press conference by dozens of players including Kobe Bryant and Carmelo Anthony, said the decision was unanimous.
Stern had urged players to take the deal on the table, saying it's the best the NBA can offer and warned that decertification is not a winning strategy.
Over the weekend, he also said he would not cancel the season this week.
Regardless, damage has already been done, in many ways.
Financially, both sides have lost hundreds of millions because of the games missed and the countless more that will be wiped out before play resumes. Team employees are losing money, and in some cases, jobs. And both the NBA and NBPA eventually must regain the loyalty of an angered fan base that wonders how the league reached this low point after such a strong 2010-11 season.
The proposal rejected by the players called for a 50-50 division of basketball-related income and proposed a 72-game season beginning Dec. 15.
On Sunday, the league made a very public push on the positives of the deal — hosting a 90-minute twitter chat to answer questions from players and fans, posting a YouTube video to explain the key points and sending a memo from Stern to players urging them to "study our proposal carefully, and to accept it as a fair compromise of the issues between us."
In the memo, posted on the league's website, Stern highlighted points of the deal and asked players to focus on the compromises the league made during negotiations, such as dropping its demands for a hard salary cap, non-guaranteed contracts and salary rollbacks.
Union officials repeatedly have said the system issues are perhaps more important to them than the split of basketball-related income, but owners say they need fundamental changes in both to allow for a chance to profit and to ensure more competitive balance throughout the league.
The previous CBA expired at the end of the day June 30. Despite a series of meetings in June, there was never much hope of a deal before that deadline, with owners wanting significant changes after saying they lost $300 million last season and hundreds of millions more in each year of the old agreement, which was ratified in 2005.
Owners wanted to keep more of the league's nearly $4 billion in basketball revenues to themselves after guaranteeing 57 percent to the players under the old deal. And they sought a system where even the smallest-market clubs could compete, believing the current system would always favor the teams who could spend the most.
Monday marked the 137th day of the lockout; the NFL lockout lasted 136 days.