Rangers are in line for a windfall without having to transfer any more players - thanks to Charlie Adam.
The former Rangers midfielder, now with Blackpool, has been the subject of failed bids from Liverpool, Birmingham City and Aston Villa.
And a sell-on clause means the Ibrox club stand to make 10% of any deal worth more than the £500,000 Blackpool paid for the 25-year-old in 2009.
The most recent bid, from Kenny Dalglish's Liverpool, was for £4m.
Any additional cash would be welcomed by Rangers, who continue to be under pressure financially from their bankers.
They were unable to persuade Kenny Miller to sign a contract extension beyond the summer and the Scotland striker was instead lured to Turkey by a lucrative offer from Bursaspor.
They don't have that passer. Charlie is their man and I don't want to stand in his way, but Liverpool's offer is totally unacceptable
Blackpool manager Ian Holloway
Rangers accepted £400,000 after allowing Miller to leave the Glasgow club during January rather than exit for nothing at the end of the season.
Following the latest rebuff from Blackpool, Scotland midfielder Adam handed in a transfer request to the Barclays Premier League club.
That has been rejected by chairman Karl Oyston, with manager Ian Holloway urging their English top-flight rivals to increase their offer if they truly want the player.
"If the player is good enough, they should sign him," said the Blackpool boss.
"They are mad not to want to buy him off us. He could replace Xabi Alonso, which is something they have still not done.
Holloway annoyed by amount offered for Adam
"They don't have that passer. Charlie is their man and I don't want to stand in his way, but Liverpool's offer is totally unacceptable."
Holloway rejects the suggestion that Adam's form could slump if he fails to win his dream move during this transfer window.
"Will I ever have the same Charlie Adam? I don't know," he said.
"But this is his first season in this division and, before our game on Saturday, we were 10th even though our total budget is less than Carlos Tevez earns in a year. Charlie has been a major part of that.
"If he loses his spirit, it would be a crying shame."
Meanwhile, despite reports linking Kris Commons with Rangers, it is believed that the Scottish champions have no plans at this stage to approach his present club, Derby County, about the winger who is out of contract in the summer.
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.