a firm's announcement of issuing stocks is general a signal that the firm's prospects are not bright, further a signal that the firm's stock price will decline.
Note: if a firm's prospects would be brighter, which means its stock price would rise; the firm would not want to sell stocks for avoiding share the rising profits with other new stockholders. It could use debt to raise money. In the opposite, if a firm's prospects would be bad, which means its stock price would fall; the firm would want to sell new stocks for sharing future losses with other new stockholders.