Looking at a portfolio of bonds, I've come across a large number of callable bonds with relatively long maturities (20 to 30 years) but very short call windows. In other words, the first and only call date (European style) will be e.g. 3 months before maturity.
I can think of two possible reasons why: either the issuer wants a small bit of flexibility for the redemption date, or there is a regulatory or similar reason.
The yield uplift for investors will be tiny - the possibility of losing 1 or 2 coupons in a 30 year bond - so that wouldn't be a reason.
What am I missing? Why would issuers do this? It's not a one-off either, I can see hundreds!