A resource squeeze is hampering Securities and Exchange Commission oversight of investment advisors, SEC Commissioner Elisse Walter told a Washington, D.C., meeting of the North American Securities Administrators Association Tuesday.

She said demands on examination staffers have not only increased because of the hedge fund and private fund advisors who were added to their workload, but also because of the new SEC oversight of municipal advisors, security-based swap entities and others.

Walter said private fund advisors have consumed a relatively large amount of staff time due to the greater amount of data the regulator needs to collect from them compared with other professionals examined.

She noted 20 percent of advisors who have been registered with the SEC for more than three years have never been examined. When recently registered are included, the “never examined” percentage climbs to 40 percent.

The commissioner was SEC Chairman from January to April of this year, holding the post between the departure of Mary Schapiro and the Senate confirmation of Mary Jo White as a commissioner. Within days after the confirmation, President Obama appointed White as chairman.

Walter said risked-based presence exams for private fund advisors have been very successful. “They’ve allowed us to meaningfully engage, assess risk, and establish a presence and credibility with a significant percentage of the new advisors,” she said.

Walter said she plans to leave the agency by the end of this year.