This paper investigates whether firms issuing securities will voluntarily disclose their private information in the absence of mandatory disclosure rules. We extend the usual model to one with two periods and show that no informed firm chooses to disclose its information in the first period if they expect a bigger fraction of shares to be sold in the second period. Informed firms can afford not to disclose their information because some firms choose to remain uninformed due to the costs of acquiring information. We also compute the optimal fraction of shares sold each period and show that the value of information increases as more firms get informed. The last result implies that in the absence of a mandatory disclosure rule, more voluntary disclosure is expected because more firms will acquire the information.