AmeriCredit Corp. is prepping a $1 billion subprime auto loan securitization. The transaction, expected to close Aug. 27, is AmeriCredit’s third this year. The loans in the securitization have an average Fico score of 572, up from 566 in AmeriCredit’s previous deal, according to a pre-sale report from Standard & Poor’s. The weighted average loan-to-value ratio increased to 110%, up from 109% in the previous deal, and the percentage of loans with 61-to-72-month terms increased to 90.5% from 89.5%. As of June 30, AmeriCredit’s portfolio in North America was $12.0 billion, up from $11.4 billion at midyear 2013. AmeriCredit is a unit of General Motors Financial Co.