“Publicly funded”? For the most part.
I saw a story the other day—kills me that I can’t remember where—that described charter schools as funded by a combination of public and private funds. That’s often the truth, isn’t it, at least among the high-performing charters people want to replicate? Yet they are almost never described that way in the press; the shorthand description is usually that charters are “public schools that operate with public funds free from many of the strictures of the school district,” or something like that.
I do not think anybody keeps track of how much private capital flows to charters (for operating costs, for buildings, for whatever). It is important to mention private funds, where they are relevant—for instance, in discussions about encouraging more charters and replicating the good ones. There are sustainability questions when any venture relies in part on philanthropy; obviously this is an issue other sectors (ahem: journalism, nonprofits) grapple with too. At any rate, I think implying charters are solely publicly funded may at times mask complexity.