The Back Bay Association (BBA) is “ready to launch” the formal process of converting to a business improvement district (BID) after two years of informal organizing.

Meg Mainzer-Cohen, president of the association, wrote to city officials last month with an update on the organization’s efforts to gather support for a formal Back Bay BID and meet financial and property targets for the area.

“As you know, the Back Bay Association has made tremendous progress toward our formation of a BID for the Back Bay,” Mainzer-Cohen wrote. “We are ready to launch a formal BID process by hiring an attorney and getting BID agreements/appeals signed by property owners.”

In order to form the BID, the association would need approval from 60 percent of the parcels and 51 percent of the total property value within its proposed boundaries. Models presented to city officials show that the association has hit those numbers. Of the 536 parcels, 395 have given their informal support for a bid, totaling over $7.2 billion in total value. Any property valued at below $4 million would not be required to pay BID fees, and so was not included in calculating the numbers.

“The BBA has done a lot of outreaches to date, and we are at a point where there is in fact a lot of support for the formation of a BID,” Mainzer-Cohen said in a phone call. “We have drafted organizational documents and are in the process of having an attorney review them. In a way, now we have to start all over again, to codify the support we know we have.”

Only three property owners are modeled as not giving approval for the BID, the largest of which is BXP (formerly Boston Properties), which owns both the Hancock and Prudential towers and is valued at over $3 billion.

“We’re not in disapproval of the Back Bay Association becoming a BID,” BXP executive vice president Bryan Koop said in a phone call. “We would just choose not to participate in the BID, because it’s a totally different organization, in terms of a business association versus a quasi-governmental agency that has the power to tax.”

Koop said BXP had thought extensively about whether it would want to be involved in the BID. He cited cost and tax concerns, and jurisdictional issues, as both its high-rises are legislated as planned development districts.

“We’re in BIDs in just about every one of our other regions,” Koop said. “Our experience leads us to have a great deal of knowledge of how most of them work, and our conclusion was that our experiences haven’t been good.”

If the BID is formed, though, BXP and other dissenters would necessarily become members of it. Mainzer-Cohen said the proposed BID boundaries would likely fall on the same lines as the association’s current boundaries. Properties like BXP, that are in the middle of that boundary, couldn’t be excluded, she said.

“We can’t adjust the boundaries to take out one in the middle,” Mainzer- Cohen said. “That would let one property owner make the decision for a number of others. If properties are on the edge of the boundary, we can give them a choice. We had a few examples on the edge, that we asked if they wanted to be included, and they all said that they did support the formation of a BID.”

The BID would be responsible for holiday lighting and planting, business advocacy and neighborhood branding, cleaning, and triaging homelessness issues. Mainzer-Cohen estimated that once the formal process starts, it would take about a year to collect signatures, but that ideally, the BID would be complete in 2026.