Abstract
Managers have incentives to strategically structure financial disclosures to limit the informativeness of public reporting and shield private information. We examine whether the SEC's mandatory Inline XBRL reporting format, phased in from 2019, constrains this incentive by rendering every tagging decision immediately visible and benchmarkable. Unlike traditional XBRL format, iXBRL reports embed machine-readable structure directly within the primary financial statement, eliminating the hidden exhibit where complexity choices and errors previously remained undetected. Using a staggered difference-in-differences design, we document a significant reduction in reporting complexity following iXBRL adoption. Discretionary extension tags decline substantially more than standardized taxonomy tags, consistent with managers reducing obfuscation. The effect concentrates among well-governed firms, while capacity-constrained firms experience rising complexity and financially distressed firms show limited improvement. Post-filing return drift declines following iXBRL adoption, confirming that the mandate lowers investors' information processing costs. We further find that the effect of iXBRL is amplified by analyst coverage.