Washington, D.C. ? James LaRue says he lost $150,000 when his instructions to his employer on where to invest money in his retirement plan were ignored.

Now the Supreme Court will decide whether a federal pension-protection law gives LaRue the right to sue to recover his losses. Arguments in the case, which has far-reaching consequences, were scheduled for today.

LaRue, who used to work at a management consulting firm, is among the 42 million workers who contributed to a 401(k) retirement plan. At issue in LaRue’s case are the limits to lawsuits under the Employee Retirement Income Security Act. It regulates private-sector retirement plans holding over $5.5 trillion in assets, including $2 trillion in an estimated quarter of a million 401(k) plans across the country.

Unlike traditional pension plans, participants in 401(k) plans – named after a section in tax law – do not know how much money they will receive in retirement. It depends on how well their chosen investments have performed.

LaRue says in 2000 and 2001 he requested changes in his investment allocations in mutual funds that were available to participants in his company’s 401(k) plan. He says the requests were not honored.