Liquidation firm Great American Group, a subsidiary of B. Riley Financial Inc. in Woodland Hills, has announced its plan to shut down a chain of nonprofit Christian bookstores and sell all the inventory. Family Christian – a retailer of Christian books, gifts and apparel that operates 237 outlets nationwide, including stores in Simi Valley and Stevenson Ranch – began its final clearance sale Feb. 25. “Great American Group’s history of working with the brand has given us leverage in knowing their merchandise and understanding their customers,” Scott Carpenter, president of Great American’s retail solutions division, said in a prepared statement. “Now our task will be discounting all of the merchandise in the stores until it is completely liquidated.” B. Riley stock (RILY) fell 4.4 percent, or 65 cents, on Monday to close at $14.20 on the Nasdaq.