Which of the following is one kind of collateral given to secure a securities loan?

U.S. Treasury Securities are frequently used as collateral to secure a securities loan because they are highly liquid, low-risk, and considered one of the safest investments available. These securities have an almost guaranteed value and are backed by the full faith and credit of the U.S. government, making them an attractive option for lenders looking to mitigate risk. Since securities lending typically involves borrowing an asset – in this case, securities – to facilitate market activities or short selling, collateral must be reliable and easily convertible to cash if needed.

In the context of the other options, while stocks, debentures, and equity securities can also serve as forms of collateral, they may not have the same level of guaranteed value or liquidity as U.S. Treasury Securities. Stocks can fluctuate widely in price, debentures involve a fixed return but are not as liquid as Treasury Securities, and equity securities may carry higher risk, depending on the company or market conditions. Thus, U.S. Treasury Securities stand out as the most secure form of collateral for this purpose.