The conservative group is working with prosecutors and two unnamed parties to reach a deal on what documents to release. U.S. District Judge Rudolph Randa had given the parties until Thursday to reach an agreement.
Wisconsin Club for Growth asked Randa for more time on Wednesday, saying the Thursday deadline is "infeasible" due to the work required to review the 3,000 pages of documents in question.
Randa agreed later Wednesday afternoon, setting a new deadline for Aug. 7.
No one has been charged in the probe.