SEC commissioners soon are expected to vote behind closed doors to approve a "pay to play proposal. The measure will curtail investment advisers ability to make political campaign contributions to elected officials who are also public pension fund trustees, if they manage money for those funds. Modeled on the Municipal Securities Rulemaking Boards Rule G-37, it is expected to offer a similar exemption for money managers on an individual basis, as the municipal securities rule, confirmed Robert E. Plaze, associate director of the SECs investment adviser division. "G-37 has an exemptive process and I would expect any rule that is adopted by the Commission would have one too, he said. Although some sources say the proposed rule could put a strain on the division of the SEC that regulates money managers, Mr. Plaze said, it would depend on the number of applications seeking exemption from the rule that the regulator receives. The MSRB rule bans government securities underwriters from doing business with government organizations for two years after making contributions to elected officials. An SEC study found alleged pay to play abuses by money managers in 17 of the 50 states. But groups representing investment advisers say the SECs proposed rule is overkill. "We believe strongly that the vast majority of investment advisers are not engaged in pay to play practices that are the focus of the current rulemaking, said Rachel S. Witmer, counsel to the Investment Counsel Association of America, which represents 240 money management firms with a total of $1.8 trillion in assets under management.