This study investigates how firms respond to restricted access to government information. Specifically, the Stop Trading on Congressional Knowledge (STOCK) Act, which limits the stock trading activities of government officials (hereafter referred to as politicians), reduces the willingness of politicians from federal executive branches to engage with firms. Utilizing this exogenous disruption in private communication, we employ a difference-in-differences approach to demonstrate that firms with significant government customers decrease the frequency of management forecasts more than other firms due to the STOCK Act. This reduction is more pronounced for firms where government sales are crucial to their performance and for those that serve as suppliers and government contractors. Further, the positive impact of the STOCK Act on voluntary disclosures is more significant for firms that ex-ante rely heavily on direct political engagements, as indicated by their discussions of political risk and political contributions, and for those expecting government support, as evidenced by higher competition levels within their industry. Conversely, the STOCK Act does not significantly affect the non-financial disclosures of these firms. Finally, consistent with findings on executive branch officers, our results indicate that congressmen are also involved in corporate communications and are effectively regulated on information exchange by the STOCK Act. Overall, these results justify the powerful supervisory impact of the STOCK Act on the U.S. government and capital market and help to facilitate a new U.S. government information disclosure policy for a fairer investment environment.