Budget has told IT provider Software Solutions Partners (SSP) that it will cease using its systems in 18 months' time.
An SSP spokesman said this week that Budget had indicated that Cheshire Datasystems (CDL) would become the preferred IT supplier for its retail network.
"As far as we are aware, Budget's preference is with CDL," said the spokesman.
"SSP has been given an 18-month run-off period."
Budget currently uses both CDL and SSP as a result of legacy systems at brokers acquired by the group.
But the broker has confirmed its intention to use one IT provider for all its branch offices.
"It has been our aim to move to one system and we are now in the advanced stages of a competitive tender process," a Budget spokeswoman said.
"We have entered into a period of exclusivity with CDL, but as yet nothing has been signed."
The spokeswoman said a deal could be finalised within the next two months.
CDL general manager Rick Slater confirmed that the tender process was at an "advanced stage", but refused to disclose details.
If Budget decided to adopt CDL as its preferred supplier, it would come as a blow to SSP which would lose out on a potentially lucrative contract, though Budget has not revealed what a preferred supplier contract with CDL would be worth.
If the deal is concluded, CDL will provide systems for the broker's retail network which employs 500 people.
Earlier this year, CDL launched the intermediary network Rebroke.net, which creates a network of intermediaries that use the CDL Classic system.
Rebroke.net enables intermediaries to pass custom to each other and retain commission on the sale without losing it to a competitor and receiving nothing.
SSP is currently running a series of regional road shows to unveil new products and services, and to discuss topics such as FSA compliance. The roadshow is scheduled to visit Scotland and Northern Ireland this week.