Corporate governance guidelines are a mechanism that a firm can enact which should reduce agency costs and better align the interests of boards and the suppliers of capital. This study examines stock price reactions primarily attributable to institutional investors occurring when corporations announce the enactment of corporate governance guidelines. A final sample of 77 firms was derived from the first announcement of corporate governance guidelines exclusive to the SEC-EDGAR database. The results indicate that good governance does matter. Firms that announced (...) the enactment of corporate governance guidelines experienced increased stock prices following the announcements. There was an immediate (days 1–4) reaction for firms that provided all or part of the guidelines’ substance; a delayed (days 8–10) reaction occurred for those firms that only referenced the guidelines’ enactment. Additionally, firms with either a potentially greater following or that had a previous history of acrimonious relations with stakeholders were rewarded by the announcement of the enactment of guidelines. (shrink)