it may sound very basic and really easy thing, but I am really facing difficulty in calculating number of periods between two dates for getting PV on fixed income section
For example, a question from CFA book (page 411) says, a 6% bond makes semianual payments on 19 March and 19 Sept and matures on 19 Sept 2026. This is to be priced for settlement on 18 June 2015, using 30/360 convention.
While calculating the PV, they use 11.5 years (23 semianual periods).
I thought it should be 2026 - 2015 = 11 years so 22 semianual periods. This approach on mine fits well in some other questions on the same topic and give me correct value for N.
Septmeber 19 2015 - September 19 2026 is 22 payments. You’re not accounting for March 19, 2015, which is also a payment. There are 23 semi-annual payments, based on the way this problem is written.
As tickersu mentioned, you are excluding the 19Mar2015 payment.
More importantly, you need to understand when calculating periods like this (2026 - 2015), you are working with “end periods” meaning the end of 2015 to the end of 2026. Any payments that come before the end of a year needs to be accounted for…below are a couple of different ways to visualize it.