A potential Department of Labor rule regarding financial professionals' fiduciary duty could render a cost-benefit analysis from the Securities and Exchange Commission moot, according to a comment letter to the SEC from Davis & Harman, a law firm representing many brokerages and mutual funds. "Virtually all responses to the [SEC's cost-benefit] request will be rendered obsolete and incorrect by the DOL fiduciary project," Davis & Harman partner Kent Mason wrote. "The SEC and the DOL should not function separately in regulating the exact same behavior. The SEC and DOL need to act on this fiduciary project together."