The Board of Regents voted unanimously against a full merger of the institutions, calling instead for a "strategic alliance."
"The board's recommendation of an alliance should not be seen as a step toward a merger," the regents said in their report, released at an afternoon meeting in College Park. "The board is convinced that maintaining these two exceptional institutions as separate entities is in the best interest of the state."
The move drew quick praise from Baltimore Mayor Stephanie Rawlings-Blake and other city leaders.
The merger's chief proponent, Senate President Thomas V. Mike Miller, did not offer an immediate comment.
The regents approved several measures intended to spur collaboration between the universities, including the creation of a joint center for medical innovation and a provision that would allow top applicants to gain joint admission to College Park and to graduate programs in Baltimore.
They also called for the universities to report their research funding, which totals more than $1 billion annually, as a single sum, a move that could vault the institutions ahead in some national rankings.
Chancellor William E. Kirwan called the proposed alliance a "much more focused and flexible structure" than a merger and said it will allow the universities to act more quickly to build partnerships where they're needed.
Jay Perman, president of the University of Maryland, Baltimore, said the alliance would create "significant value through formal and accountable collaboration while allowing both institutions to keep the autonomy that has made them great."
Though the College Park campus was more supportive of a full merger, President Wallace Loh also praised the plan that emerged Friday.
"It is not either merger or no merger," he said. "There has always been a continuum of opportunity. My position had never been in favor of a merger. I was always in favor of an option in between."
The merger idea came from Miller, a graduate of both institutions, who argued that they could achieve greater prestige and research clout together than they ever could apart.
Miller, who has an undergraduate degree from College Park and a law degree from Baltimore, championed legislation in the General Assembly this year that required the regents to study the issue and submit a report by Dec. 15.
The General Assembly is not required to take any action on the report approved Friday. It could simply accept the recommendations and allow the universities to follow the regents' blueprint.
Kirwan said he had already spoken with many legislators about the content of the report.
"What we've done is very consistent with what I heard from them that they wanted as an outcome," the chancellor said. "I think they have always shown great deference and respect in accepting the board's guidance."
A spokeswoman for Miller said he was still reviewing the report on Friday and did not have an immediate comment.
Kirwan said Miller had expressed satisfaction with many of the collaborations proposed in the report, though the Senate president had reservations about the term "strategic alliance."
"He said an alliance is something that can be broken," Kirwan said.
But the Senate president had said recently that using the term merger was a mistake, because it implied that the College Park campus would absorb its Baltimore counterpart. He said it was never his intention to rob Baltimore's campus of autonomous leadership.
Civic and campus leaders in College Park rallied around the merger idea, saying the research interests of the two campuses would blend perfectly and that undergraduates on the flagship campus would benefit from access to top medical and legal researchers in Baltimore.
"Without a merger, what we see in the historical record — a lack of major collaborations and a number of missed opportunities — is what we'll get in the future," said former College Park President C.D. "Dan" Mote.
But the idea drew bitter opposition from Baltimore leaders, including Rawlings-Blake, who argued that a merger would be the equivalent of the city losing a major corporate headquarters.
Rawlings-Blake praised UMB as a key force in west-side redevelopment and said the university's impact in city neighborhoods could be diminished if its leaders were relocated to College Park.
"The mayor is very pleased to learn about the vote," spokesman Ryan O'Doherty said after Friday's meeting. "She has always supported the idea of increased collaboration."
Students and faculty at the Baltimore campus also opposed the merger, as did the leaders of other universities in the system, who said they would struggle to compete for resources with the resulting research giant.
"A merger, to be successful, has to have unified support across the two organizations," Kirwan said. "And we didn't have that."
Even critics of the proposal said the institutions could benefit from more substantial collaboration.
The regents recommended the creation of a joint operation devoted to creating businesses from the research performed on both campuses. They asked the campuses to create joint programs in bioscience and biomedical research, public policy, law, sociology and social services. Finally, they asked the universities to facilitate joint faculty appointments so top researchers aren't limited to one campus.
"I think we all agree this alliance creates a tremendous potential for collaboration and greatness," said Regent Gary L. Attman.
Fellow board member Tom McMillen praised the plan, but added that he worries about a potential lack of funding for the new joint programs.
"My concern here is that we're going into an indeterminate fiscal climate in the state," he said. "What happens if there is no money? Can we still make this happen? We still have to find a way to have some accomplishment, even if resources are very meager."
Loh echoed those concerns.
"I have a philosophy that no money equals no mission," he said. "I think that if you are going to do a new collaboration with new things, it's going to cost money."
The regents called for Kirwan, Loh and Perman to compose an action plan incorporating the recommendations by March 1.
The next two months, Loh said, "are where the rubber meets the road."