Broker Dealers must submit an annual independent certified audit to both FINRA, the SEC, and SIPC (if applicable). These annual audits must be submitted no later than 60 days after fiscal year end. For example if year end is December 31, 2017 the annual audit is due to regulators no later than March 1, 2018. More regulatory due dates for Broker Dealers can be found here.
FINRA has available various templates, compliance tools, and a compliance calendar on their website. You can access more specific information here.