Mayor Nutter this morning announced something he's calling the "Sandy Hook Principles" - a list of 20 measures to curb gun violence - that companies making or selling guns and ammunition must support to avoid "economic divestment actions."
The most likely consequence companies could face would be the withdrawal of any investment from the city pension fund.
The principles, named for the Connecticut elementary school where a gunman killed 20 children and six adults last month, are modeled on a similar approach that placed economic pressure on South African companies during Apartheid.
Nutter also said today that city Solicitor Shelley Smith, who sits on the pension board, would introduce a resolution at a meeting next week for the board to adopt the Sandy Hook Principles.
On Monday, Chicago Mayor Rahm Emmanuel said he would ask all his city's pension funds to investigate whether they have any holdings in assault weapons makers and sellers, a step toward divesting of those companies.
Funds in several states, including New York and Massachusetts, have begun checking their portfolios for investments in firearm manufacturers as well.
Cerberus Capital Management announced last month that it would sell the Freedom Group - the maker of the Bushmaster rifle used in the Sandy Hook massacre - shortly after hearing concerns from a powerful client, the California teachers' pension fund.
Nutter's plan differs because he's not asking for funds to divest, but to make investments in gun makers and sellers - including retail giant Wal-Mart — contingent upon them actively supporting a list of measures, such as universal background checks on all gun and ammunition sales.
There are 20 principles in all, and most are likely either to be hailed as sensible steps for choking off the secondary black market of illegal guns, or reviled as intolerable attacks on the Second Amendment.
Nutter said he hopes the idea of the principles spreads organically and gets adopted by cities, universities, hedge funds — any organization that holds investments with private corporations.