This study finds that pro-forma earnings forecasts by bidding firms during acquisitions are associated with a higher likelihood of deal completion, expedited deal closing, and with a lower acquisition premium − but only in stock-financed acquisitions. Analysts also respond to these forecasts by revising their forecasts for the bidder upward. However, the benefits of forecast disclosure only accrue to bidders with a strong forecasting reputation prior to the acquisition. Explaining why not all bidders forecast, we document a higher likelihood of post-merger litigation and CEO turnover for bidders with a weak forecasting reputation and for those that underperform post-merger. •Bidder pro-forma forecasts are associated with higher likelihood of deal completion.•Forecasts lead to lower takeover premia and analyst consensus upgrades.•Forecasts play a more important role in stock-financed acquisitions.•The benefits of forecasting only accrue to bidders with a strong forecasting reputation.•Forecasting costs include a higher litigation likelihood and management turnover.