Does voluntary disclosure on an internet platform affect analyst forecast accuracy?

We explore how voluntary disclosure on an Internet platform affects analyst behaviour. We find that the higher the level of voluntary disclosure on the 'hudongyi' platform of China's Shenzhen Stock Exchange, the greater the error in analyst forecasts. Voluntary disclosure on this platform provides analysts with heuristic clues, and heuristic cognitive biases increase analysts' forecasting errors. In addition, social media has a partial mediation effect between voluntary disclosure and analyst forecast errors.