A type of investment often used to accommodate requirements of the Uniform Principal and Income Act (UPIA) for uninvested fiduciary cash overnight is a:

The correct choice is money market investments, which are designed to manage short-term cash needs while providing liquidity and a slightly higher return compared to traditional cash holdings. Under the Uniform Principal and Income Act (UPIA), fiduciaries must balance the needs of income beneficiaries with those of remainder beneficiaries, which often requires careful cash management. Money market funds meet these requirements effectively because they are low-risk investments that can accommodate short-term cash needs.

These funds primarily invest in highly liquid and short-term financial instruments, making them ideal for overnight cash management. They provide immediate access to cash and maintain a stable value, aligning well with the fiduciary's obligation to safeguard the principal while generating some income.

While cash deposits, such as CDs, provide stability, they typically require a longer commitment of funds, impacting liquidity. Banker's acceptances and repos serve specific financing or investment strategies but do not primarily focus on meeting the short-term liquidity needs required under UPIA as effectively as money market investments do. Thus, the use of a money market fund is the most suitable choice for accommodating uninvested fiduciary cash overnight, aligning with the UPIA’s intentions.