But they were hit with a new petition just seven days later after they missed a payment.
The arrival of Malaysian businessman Datuk Chan Tien Ghee onto the club's board gave hope of fresh investment.
But the emergence of the Americans could be the most significant development long term.
Cardiff also have a long-standing £15m debt with former owner Sam Hammam's Langston Corporation, but have reached a payment settlement.
With the Bluebirds struggling for cash, but in contention for promotion to the Premier League, the Bluebirds sold more than 10,000 season tickets as expectant fans reacted to Ridsdale's promise that the investment would pay for new players in January.
His transfer kitty was inflated by an estimated £3m thanks to their season ticket initiative which the club promised would see supporters gain a full refund on their 2010/11 passes should Cardiff win top-flight promotion.
But the club have since said no players will come in until the tax bill is paid.
Bookmark with:
What are these?