Final answer:
Banks are not major investors in U.S. equities compared to mutual funds, pension funds, and hedge funds, due to the stringent regulations that limit their speculative investments to safeguard depositors' funds.
Step-by-step explanation:
The question asks which of the given institutions are not major investors in U.S. equities. Major investors in U.S. equities typically include mutual funds, pension funds, and hedge funds, as these entities often invest in stocks to generate returns for their clients or beneficiaries. On the other hand, banks are highly regulated institutions and usually do not represent major direct investors in equities due to restrictions that limit speculative investments to protect depositors' money. Hence, banks are not major investors in U.S. equities compared to the other options provided.