Why is the allotment value for my T-bill purchase lesser than the face value of Rs 100?
T-bills do not carry an interest component, in fact, this is one of the biggest difference between T-bills and Bonds. T-bills are issued at a discount to their true (PAR) value and upon expiry, its redeemed at its true value.
Ex- Assume the true value (also called the Par value), is Rs.100. This T-bill is issued to you at a discount to its par value, Say Rs.97. After 91 days, you will get back Rs.100 and therefore you make a return of Rs.3.
This is why the allotment value shown on Coin, will be lesser than the Par value of Rs 10000 (or multiple of 10000)