Boston Mayor Martin Walsh has decided on a private resolution regarding the fate of the Kenmore Square Citgo sign Thursday that would allow the sign to remain, without designating it a landmark.

The status of the sign, which has been an icon of the Boston skyline for decades, fell into question when the building beneath it was sold by Boston University to Related Beal, a real estate development firm, in 2016.

The Boston Landmark Commission voted unanimously Nov. 13 to designate the Citgo sign a landmark, which would have ensured the sign’s protection against demolition or obstruction. Walsh said the private resolution would ensure the Citgo sign remains in place for years to come.

“We are pleased to share that we have reached a long-term resolution that will preserve the Citgo sign and allow for it to remain in place in Kenmore Square for years to come, recognizing the significance that this sign has on our landscape in Boston, while balancing the opportunity for our horizons to continue evolving in future years,” a joint statement from Walsh, Citgo, Related Beal and Boston University read.

Walsh’s office and Related Beal declined to comment further.

The Citgo sign may pose different obstacles to Related Beal’s development plans in the Kenmore area. Alison Frazee, director of advocacy at the Boston Preservation Alliance, wrote in an email that the alliance is uneasy about the mayor’s resolution.

“While the Alliance is pleased that there is an agreement to maintain the iconic Citgo Sign, and our biggest concern – losing the sign – seems to be off the table, the details of this agreement are crucial to the future of the sign and its presence on the skyline and in Kenmore Square,” Frazee wrote.

The terms of the resolution have not yet been disclosed by the mayor’s office, nor by Related Beal.

Frazee wrote that Alliance is disappointed by the lack of input they were given in the mayor’s resolution.

“And we are shocked and dismayed that none of us, the Alliance nor BLC, who have been meticulously working through the Landmarking process over the course of over two years, were included in the discussion about whether this deal meets preservation goals and standards,” she wrote.

Without the sign being designated a landmark, Frazee wrote that the Citgo sign is “not truly protected.”

Boston University spokesperson Colin Riley said the university wanted the sign to remain on campus.

“I’d say we’re very pleased that there’s an agreement and that the Citgo sign will continue,” Riley said. “We’re very pleased, and the mayor deserves a lot of credit for making that happen.”

Jasmine Bridgewaters, 57, of downtown Boston, said she did not see the need for the demolition and reconstruction of buildings in Kenmore Square.

“It’s crowded enough out here,” Bridgewaters said. “Why spend all that money you don’t need to spend to tear it down and rebuild when there’s nothing wrong with that building?”

Gerardo Rivas, 33, of Brighton, said he has mixed feelings about the development of Kenmore Square.

“If you’re trying to get more business here, for some people, that will be OK,” Revas said. “For the people that live here, it will change a lot.”

Rita Salvucci, 58, said she does not support the plans for the new development.

“I don’t want them to move the Citgo sign,” the Newtonville resident said. “I like Kenmore Square just the way it is.”

Guthrie Kuckes contributed to the reporting of this story.