Hull KR say talks with potential investor Tony Larvin will cease on 31 January whether or not an agreement is reached.
The businessman first held discussions with the Super League club before Christmas, and Rovers later confirmed he was proposing a "substantial investment."
But an 11 January statement said Larvin was yet to provide "proof of funds", and further talks have so far failed to yield a deal.
The Super League season is less than two weeks away, and both Larvin and Rovers want the issue sorted by the time they take on Catalan Dragons on 3 February.
A new statement read: "Hull Kingston Rovers can confirm that they are still in talks with Tony Larvin regarding his potential investment into the club.
"Both parties accept a conclusion needs to be reached soon so that the club can focus on the forthcoming season. Therefore, a resolution is expected by 31 January."