From Academy Bylaws:
Article III, Section 1. Membership shall be by invitation of the Board of Governors. Invitations to active membership shall be limited to those persons active in the motion picture arts and sciences, or credited with screen achievements, or who have otherwise achieved distinction in the motion picture arts and sciences and who, in the opinion of the Board, are qualified for membership.
To be considered for invitation to membership in the Producers Branch of the Academy, a candidate must meet one of the requirements below (clause a, b or c), and have performed the majority of producing functions on theatrical feature films of a caliber which, in the opinion of the executive committee, reflect the high standards of the Academy.
In general, candidates must play a major role in originating and overseeing the projects on which they have received credit. Normally, at least one of the credits must be for a picture released within the most recent ten years.
Individuals who receive producer credit but function primarily as talent managers, financiers, executives, sales agents or artists primarily performing other key roles (e.g., actor, director, writer), will generally not be considered for membership in the Producers Branch.
(a) a candidate must either:
(a.i) have earned the PGA “mark” as a credited producer on three theatrical feature films, regardless of the number of additional persons receiving the “mark.”
or
(a.ii) have earned a minimum of 2.0 producer points, based on the number of persons who share a producer or “produced by” credit on each film. Points are calculated by the appropriate fraction for each film: e.g., a producer credit shared by two individuals is calculated as 0.5 for each; three producers is 0.33; four producers is 0.25 and so on.
• On films where the producer received the PGA “mark,” the calculation is based on the number of producers earning the “mark” on each film.
• Producers who share credit (but have not earned the “mark”) still receive the fraction based on the total number of credited producers. The points do not include executive producer, co-producer, associate producer, line producer, “produced in association with,” or any other credit.
or
(b) have been an Academy Award-eligible producer on a picture nominated by the Academy for the Best Picture award.
or
(c) have, in the judgment of the Producers Branch Executive Committee, otherwise achieved unique distinction, earned special merit or made an outstanding contribution as a motion picture producer.
Proposals must be accompanied by a letter from each sponsor which addresses, as specifically as possible, how the candidate meets one or another of the requirements above.