Short answers, pulled from the story.
The National Basketball Association introduced a salary cap in the mid-1940s for one season before abolishing it. The league reinstated the salary cap system during the 1984, 85 season with an initial limit of $4.6 million per team.
For the 2024, 25 season, the NBA salary cap sits at $140.588 million under the Collective Bargaining Agreement ratified in July 2017. Teams must spend 90 percent of this cap amount each year to meet minimum spending requirements.
Unlike the NFL or NHL which enforce hard caps forbidding teams from exceeding limits, the NBA utilizes a soft salary cap structure that allows teams to go above the cap while facing reduced privileges in free agency. Teams that exceed the luxury tax threshold face financial penalties known as the luxury tax calculated through a complex formula based on how far payroll surpasses specific dollar amounts.
Stephen Curry signed the first supermax deal worth $201 million running through the 2021, 22 season on the 6th of July 2017. This Designated Veteran Player Extension known as the Kevin Durant Rule lets teams offer contracts between 30 and 35 percent of the salary cap to homegrown stars.
In the 2017, 18 season, the Mid-Level Exception started at $8.406 million for teams over the cap but under the luxury tax apron. Teams above the apron received an initial Mid-Level Exception of $5.192 million allowing contracts up to three years long.