The Choir Academy of Chicago Charter School must raise $150,000 in three weeks to stay open, officials say. The financial trouble began last fall. The Choir Academy's enrollment dropped from 200 to 165 when the academy relocated, thus lowering the charter school's share of state funds. The academy mistakenly continued to collect a rent subsidy after it moved from leased space in a Catholic school to district-owned space in Abbott Elementary School. The money has been repaid, but the school's balance sheet worsened as a result.