Abstract: Financial Services Authority (FSA) is an independent agency and out of from interference by other parties. FSA has the functions, duties and authority of regulation, supervision, inspection and investigation in the financial services sector. FSA to function organized system of regulation and supervision is integrated to the overall activities in the financial services sector. The purpose of this study was to Determine the abnormal return (AR) on stocks in the banking sub-sector and the effect of policies FSA. Method of research is event study that could see the influence before and after the event, and then were Analyzed by t-test pired. The result showed that there was no influence of the events under investigation on stock returns in the banking sub-sector and stock movement patterns that tend range more towards the negative visible from Cumulative Average Abnormal Return (caar).