A corporation must file a federal income tax return on Form 1120 on or before the fifteenth day of the third month following the close of each fiscal year.
A California corporation (or a corporation doing business in California) must file a California corporate income tax return on Form 100 on or before the fifteenth day of the third month following the close of each taxable year. California corporations are generally subject to an annual minimum tax of $800. If you have qualified in states other than Delaware, you should consult competent advisors regarding not only annual qualification fees, but tax return obligations also.