台灣會計師更換之市場反應

The Market Reactions Subsequent to Auditor Switches in Taiwan

本文探討台灣會計師更換之市場反應，包含企業更換會計師之方向、原因與時點之影響。本文以人工方式收集自1993年到2012年間，497筆在公開資訊觀測站上揭露之會計師更換宣告。實證結果顯示，規模較大的公司若由大型事務所更換到非大型事務所，市場給予顯著負面評價，若由非大型事務所更換至大型事務所，則市場給予顯著正面評價。此外，若會計師更換的原因為會計師辭職時，市場將給予顯著負面評價。當規模較大企業跟隨原簽證會計師由非大型事務所更換到大型事務所時，股價報酬顯著為負。更換會計師時點對於企業股價報酬有顯著影響，若企業在當年第一季之前（含）更換當年會計師，市場將給予正面評價。另一方面，與美國研究不同，台灣資本市場對於會計師更換前期之審計意見，或者更換宣告中是否載明會計師對於企業內部控制有重大建議事項並未有顯著反應。本文實證結果可供企業、會計師、投資人與監管機構參考。

This study investigates the market reactions subsequent to auditor switches in Taiwan. We focus on the directions, reasons for, and timings of auditor switches. Using 497 observations of auditor switch, which were hand-collected at the Market Observation Post System the of Taiwan Stock Exchange for the period between 1993 and 2012, we reveal that the market reacts negatively (positively) when a large company switched from a Big N (non-Big N) audit firm to its non-Big N (Big N) counterpart. Furthermore, the market reacts negatively when an auditor resigned or when a large company followed the auditor from a non-Big N to a Big N auditor. The timing of auditor switches is also shown to affect market reactions; i.e., the market tends to react positively to auditor switches in the first quarter. Unlike previous studies conducted in the U.S., the capital market in Taiwan appears not to react to preceding auditors' modified audit opinions prior to auditor switch or to audit reports indicating internal control weaknesses. This study has implications for companies, auditors, investors, and regulators.