Boston Mayor Marty Walsh, on his way out of office, is maneuvering to require developers to toss in more cash for affordable housing when they look to pursue big projects.

Developers could see linkage fees on sites 100K SF and up rise 42%, from today's $10.81 per SF to $15.39 per SF, Walsh announced Tuesday. The proposal is the developer-friendly Walsh's latest push to champion affordable housing efforts as he's on the verge of joining the Biden administration to become the next Secretary of Labor.

"By increasing Linkage requirements, we will substantially increase revenue streams to fund the affordable housing and workforce training programs that will help our residents recover and thrive in a post-COVID economy,” Walsh said in a statement.

The fee, which generated $51.7M last year, would have created $73.6M combined in affordable housing and workforce training funds under the proposed new threshold, the Boston Globe reported. City law requires developers to make a fraction of newly built units available to buyers at an income level at 70% of average median income. Currently, just under half of Boston's residents make less than 60% AMI, city councilors said in a meeting Wednesday.

The change would apply to projects that haven't started the formal Boston Planning and Development Agency review process. Developers who have submitted letters of intent could be subject to the raise, as the fee hike could be approved as soon as next week.

At least eight large projects, from residential to mixed-use lab and office plans, would pay the fees exceeding the $1.5M required for a 100K SF building. Among newly announced projects are WS Development's joint venture with the Boston Red Sox to reshape the blocks surrounding Fenway Park.

Also possible subject to the higher fee: Center Court Partners, which submitted an LOI Tuesday to build a 250K SF life science building and a 445K SF residential building near the former Boston Globe headquarters on Morrissey Boulevard in Dorchester.

City officials determined the new rate based on “several years” of feasibility studies, conversations with developers and rising construction costs, according to Tuesday's statement. For each square foot, $13 would go toward affordable housing and $2.39 would go to workforce training.

The BPDA previously adjusted the fee every three years based on inflation, but recent legislation on Beacon Hill has allowed city leaders more flexibility in amending zoning and building laws.

The hike could be enacted as soon as the end of next week by city committees, possibly before Walsh's potential confirmation. City Council President Kim Janey would become acting mayor when Walsh departs.