You mentioned all the downsides I thought of when I looked at this - floating rate based on LIBOR, which is set to disappear in 2020 - then what happens to the yield? Even stranger, dividendchannel.com says Ally didn't get a dime from these preferreds - who did if that's true?
GMAC Capital Trust I 8.125% Fixed Rate/Floating Rate Trust Preferred Securities, Series 2 (ALLY.PRA)
Prospectus excerpt: The United States Department of the Treasury is selling the 8.125% Fixed Rate/Floating Rate Trust Preferred Securities, Series 2 of GMAC Capital Trust I. Ally Financial Inc. will not receive any proceeds from the sale of Series 2 Trust Preferred Securities by the Selling Securityholder.