at&t preferred stock below $25

Stocks A to Z
1

I have a basic idea about preferred stocks and consider that the mean stock price should be about $25.00 ( i.e. the call value). What is the reasoning for the following -

AT&T INC 4.7 DP SHS PFD C T/PRC:NYSE

to be considerably below $25.00 ? (price this AM of $21.16).

Why so low below the call value ?

math999man

Thanks.