Short selling t-bills instead of margin loan

[ajacobson]

If you are doing the SPX box - ask your broker to price the box as a single trade. In the crowd, the box is quoted by yield. You increase your transaction costs, depending on the broker maybe a buck or two for the entire box. During RTH you should be quoted in a minute or so. If your broker can't or won't do it, you might want to consider another broker.

 

[hajimow]

If you short $250k tbill with $500, it does not mean that you can use that $250k to buy a risky stock and go bankrupt. Then how you are going to buy the tbill on maturity. The way it works is that the money will be kept in your account so you be able to cover it at any minute. If rates go up and and the bond prices drop, then you can use the difference but if the rate goes down, then you need to have more cash to hold that position. In IB , you will get about 4.8% for 150k of that money and you will pay 5.4% for that 250k