Investment bank Seymour Pierce has warned it will take control of Birmingham City unless the club's current owners come up with a £2.2million payment before the end of May.
Last month, the bank run by Keith Harris launched court action to recover £2.2million it claims to be owed following Carson Yeung's takeover of the club.
Yeung's Grandtop investment company took over at St Andrew's in October 2009, but the fee is believed to relate to the groundwork put in by Seymour Pierce when the Hong Kong businessman first became involved with the Blues in 2007.
Lawyers working for Seymour Pierce won a court order requiring Yeung to pay the amount by Monday.
However, with the sum remaining outstanding, Seymour Pierce can now gain a charge of the shares held by Yeung's company, Birmingham International Holdings.
"Seymour Pierce can take a charge over the shares of Birmingham City and do what they need to do with them to recover the money it is owed, so that means they could potentially sell them to another owner," Seymour Pierce spokesman Neil Bennett told Sky Sports News.