This study investigates whether the eXtensible Business Reporting Language (XBRL) reporting format provides incremental information value beyond the same 10K/10Q filings previously provided in HTML format. Using a sample from the XBRL Voluntary Filing Program, we document a significant increase in stock price variance on the day when voluntary XBRL reports are filed. We find market response is stronger when more content is filed on the same day. To evaluate relative information value, we decompose the quarterly return variance for three primary news announcements related to earnings including earnings announcement, HTML filing, and XBRL filing. We find XBRL filings have larger relative information value than HTML filings. Our results indicate that the XBRL reporting format provides incremental information content.