Talk:Day count convention

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I believe that there are errors in the 30/360 daycount description. I would suggest the following instead:

The number of days from M1/D1/Y1 to M2/D2/Y2 is computed according to the following procedure:

1. If D1 is 31, change D1 to 30.

2. If D2 is 31 and D1 is 30 or 31, then change D2 to 30.

3. If M1 is 2, and D1 is 28 (in a non-leap year) or 29, then change D1 to 30.

Then the number of days, N is:

N = 360(Y2 - Y1) + 30(M2 - M1) + (D2 - D1)

I have not seen the increase rule ever (for case where date2 is 31 and date1 is less than 30), and the February rule is confusingly placed as a variation. However, the current version has had so much effort put into it, maybe it is more common.

[edit] Day Adjust Rule

This article should like to an article on Day Adjust rules that tell you what to do on non-trading days.

I believe no article exists at the moment... but if someone knows about Modified following etc then it would be a good addition.