International Brotherhood of Teamsters v. Daniel, 439 U.S. 551 (1979)

A non-contributory compulsory pension plan did not constitute an "investment contract" for purposes of the Securities Exchange Act of 1934 under the Howey test given that there was no investment of money into the plan by the employee (he sold his labour primarily to obtain a livelihood rather than in return for the employer's contribution to the plan), and because the pension plan could not be regarded as a common venture based on a reasonable expectation of profits to be derived from the entrepreneurial or managerial efforts of others (the return to the employee rested primarily upon employer contributions and on the employee's ability to meet the substantial pre-conditions to vesting, rather than on the investment performance of the plan).

At 566:

"It is a commonplace in our jurisprudence that an administrative agency's consistent, longstanding interpretation of the statute under which it operates is entitled to considerable weight ... This deference is a product both of an awareness of the practical expertise which an agency normally develops, and of a willingness to accord some measure of flexibility to such an agency as it encounters new and unforeseen problems over time. But this deference is constrained by our obligation to honor the clear meaning of a statute, as revealed by its language, purpose and history."