Using a unique setting where stand-alone banks submit filings to bank regulators instead of the U.S. Securities and Exchange Commission (SEC), we examine the consequences of fragmented securities regulation for information-processing costs and opportunistic insider trading. We find the market reaction to insider-trading filings on FDICconnect less timely than to those on SEC's Electronic Data Gathering, Analysis, and Retrieval (EDGAR) system, suggesting FDICconnect generates higher information-processing costs. We also find only large investors trade more on insider-trading filings on FDICconnect than on insider-trading filings on SEC EDGAR, thus extracting benefits from the delayed market reaction to insider-trading filings on FDICconnect. Finally, we find increased insider selling in stand-alone banks prior to negative earnings news, suggesting insiders' opportunistic use of private information. These findings collectively suggest regulatory fragmentation undermines market efficiency and distorts the level playing field.