The NIH is proposing a grant cap that could help some labs and strain others

The National Institutes of Health (NIH) has issued a formal Request for Information (RFI) regarding a proposal to limit the number of Research Project Grants (RPGs) an individual investigator can hold simultaneously. The agency is considering caps ranging from two to four grants per Principal Investigator (PI) or Multi-Principal Investigator (MPI). 

A cap of four grants could free up to $3.5 billion, allowing the NIH to support more researchers, the agency said. Public comments on the proposal are being accepted through August 3. 

The RFI states the cap will ensure funding reaches a more diverse set of geographic regions and increase support for early-stage investigators and mid-career researchers. The proposal cites research that suggests smaller research teams produce more transformational work than large, complex hierarchies. For labs facing a loss of grant support, the policy could translate into fewer research projects and, in some medical centers, pressure on faculty salaries. 

More funding can translate into diminishing returns at large labs

One paper, published in Nature Biotechnology and cited in the RFI, found that as team sizes grow, the probability of junior scientists securing research funding or obtaining tenure decreases, while the likelihood of exiting academia increases. The paper concluded that team sizes increased when the NIH budget doubled between 1998 and 2003. 

“It is true that when the NIH budget doubled, the grants got larger, and that’s because in the NIH review process, the experienced investigator is more likely to get funding,” said Donna Ginther, a co-author of the paper. “If the goal is to fund more young investigators, I think [a cap] makes a lot of sense, but it’s really complicated because there are all these moving parts.”

The NIH also cited studies indicating that the marginal productivity per grant dollar begins to taper off as a lab’s total funding increases. One bioRxiv preprint found that once the amount of funding is approximately equal to three R01 grants, marginal returns decrease significantly. The paper suggests that this decrease in return could result from large, inefficient teams. 

A cap could threaten some smaller labs

The agency argues that the cap would affect a small portion of the research community. In 2025, only 10.7% of PIs held three or more RPGs and only 1.2% held five or more. 

A two-grant cap could allow the NIH to support an additional 5,230 PIs. A three-grant cap would support 3,020, and a four-grant cap would support 1,900. 

There were a lot of changes to the scientific review process that need to be evaluated to see if the funds were more broadly distributed, and then, if that was the case, did a broader distribution of funds produce better science?” said Ginther. “If you cap the number of grants, it may affect the amount of science being performed.”

“What if there’s a huge priority of the NIH with Alzheimer’s and the lead investigator comes in, has a great new idea, and wants whatever x plus one grant is? With any policy decision, you’re going to have opportunity costs associated with it,” she added. A hard cap eliminates the option for administrative flexibility. 

“If the goal is to produce science and new scientists, those larger labs are probably able to manage their resources in a way to continue to do that, whereas a smaller lab is one grant cancellation away from closing,” Ginther said. 

At medical center, grants are used to fund faculty and researcher salaries. “If you work at a medical center, you need to fund a significant portion of your salary with grants, and so the incentives for a medical school faculty to have multiple grants are the difference between eating and not eating,” said Ginther. 

For instance, Stanford’s School of Medicine faculty handbook says grants and contracts provide salary support only for research-related activities, requires other sources for non-research effort, and says Research Line faculty are generally expected to have 80% of salary and benefits supported from external sources by the end of the third year.

A cap on R01s could cause investigators to shift to other mechanisms, like the NIH P-Series grant (P grants) for large-scale medical research centers. “Right now, everybody is looking for resources and trying to diversify their portfolio. I think a grant cap will just accelerate that move,” Ginther said. 

A revival of a 2017 proposal that faced backlash 

The NIH proposes two methods for transitioning into the caps. The first is a phased reduction plan, where institutions would be unable to accept competing renewal (Type 2) grants for a PI over the cap unless they reduced their total grant count by one. To accept a new grant (Type 1), the institution would have to relinquish existing awards to reach the cap immediately. 

The second option is an accelerated transition, where all institutions would have to bring their PIs into compliance with the cap within one year. They could do this by asking the NIH to end a grant at the conclusion of its current budget period, or seeking NIH approval to move the grant to another researcher within the institution. 

This proposal is a revival of the 2017 “Grant Support Index” (GSI), which sought to limit investigators to the equivalent of three R01 grants. The plan was abandoned after five weeks, following significant backlash from the scientific community. The new proposal cites many of the same studies. It also uses grant count rather than the point-based system proposed in 2017. 

Michael Lauer, who led the NIH’s extramural research office when the GSI was proposed, told Science he had “mixed feelings” about seeing his office’s proposal revived. “It makes sense to spread the wealth,” he said, but a grant cap “fails to address the root problems.” 

“I would encourage the NIH to take a holistic view of why multiple grants are happening in the first place, and also a holistic view of how other policy changes that have been made in the past decade may have affected where the funding is going,” said Ginther. “I think to craft the optimal policy, it would be important for the NIH to think about the real value of grants and think about all the changes that have been made.”