This paper uses intraday U.S. bond transaction and stock quote data to investigate whether corporate bonds lead stocks in price discovery of underlying firm value. I use Hasbrouck's (1995) “information share" approach to determine the relative contribution of corporate bond to price discovery. Based on a sample of 214 firms, I find that corporate bond markets contribute 12.6% on average to price discovery from 2009 to 2011. Corporate bond market price discovery increases with the riskiness of the under-lying firm value, and is related to contemporaneous market conditions. The findings are consistent with the informed trading theory and Merton (1973) model.