Should Birmingham survive next season in the top flight then another half a million is due.
'Cardiff will benefit from us going up by £500,000 now and if we stay up in the Premiership I'll happily send another £500,000 down to Cardiff. I could not think of a better club to send the money to," said Sullivan.
'It is just disappointing they were not promoted with us. But Cardiff couldn't keep up the start they had and that's a shame.'