An investigation in Philadelphia finds that some charters now spend more on paying down the debt of lavish facilities than they spend on instruction. "There's no real scrutiny of these deals, and charters end up saddled with big fixed costs. Charter schools used to inhabit repurposed supermarkets or old storefronts, but a Philly.com analysis of bond documents showed that one out of three charters today - have bought or constructed newer and larger school buildings with tax-exempt bonds, paying millions in debt and fees to consultants along the way... Bonds - school debt sold to investors who are gradually paid back with interest - have become popular among charters because they allow lower borrowing costs than standard commercial loans."This leaves charters spending more education dollars on interest payments - at rates that are double or triple what the district pays."