Alternate names: Prudent person rule
For example, a mutual fund manager is required to adhere to the prudent investor rule. When investors buy into the fund, the manager inherits a fiduciary responsibility to make decisions for the fund based on the fund’s strategy. Fund managers must also ensure that they do their utmost to protect investors’ assets and grow the fund’s value with educated and reasonable investment choices. Although it isn’t always possible to keep investments from losing value, the fund managers must do their best to mitigate losses.
How Does the Prudent Investor Rule Work?
When it was written, the prudent investor rule applied to each investment individually. However, as more people began to understand how diversification helps, the rule was changed to reflect the Modern Portfolio Theory (MPT), which explains why portfolios should be diversified. MPT allows for greater risks on individual investments, as long as the risks are reasonable and balanced by the portfolio. Under this theory, risks are managed while keeping the potential for gains. In general, you can expect a trustee following the prudent investor rule:
To diversify assets to reduce as much risk as possible. To maintain enough liquidity (including bonds and FDIC-insured deposits) to fund cash flow needs and avoid being forced to sell when prices have dropped. To judge each security or investment position in the portfolio on its own stand-alone merits and reject any that are too risky. To remain loyal to the person for whom they are managing money by fully disclosing any decisions. To regularly monitor investments for fundamental changes in the nature or risks of the holdings.
Legal Ramifications
If your trustee breaches the prudent investor rule, you may be able to sue for damages. You’ll need to prove that they took an unreasonably risky position on purpose. Portfolio losses alone won’t help you win, especially during recessions (when many people lose money). To win a case, you must prove not just that your investment did poorly but also that the trustee was the cause for its poor performance. For instance, you may have a strong case if they used margin debt or put 50% of your assets in a single biotech stock that was awaiting FDA approval for a new wonder drug.
The History of the Prudent Investor Rule
Though the concept has been updated, the prudent investor rule’s origins date to the early 1800s and a wealthy man named John McLean. When he died, he left money in a trust meant to provide his wife with passive income. Upon her death, McLean instructed that the remaining funds were to be divided between two charitable beneficiaries, Harvard College and Massachusetts General Hospital. However, when they finally received the donations, it was far less than they expected. They sued the trustee, pointing to evidence that the trust had lost value because of investment choices. The case made it to the Massachusetts Supreme Court, where, in 1830, Justice Samuel Putnam’s opinion included the now-famous passage:
