(1) Effective for tax years beginning after December 31, 1993, every corporation must make estimated tax payments if its annual tax is $5,000 or more.

(2) The $5,000 threshold includes any applicable surtax.

(3) If the $5,000 threshold is met, the taxpayer has the option of submitting 80% of the current year's tax liability in estimated payments or 100% of last year's liability provided that the preceding taxable year was a period of 12 months and a return was filed for the preceding taxable year. By submitting four equal quarterly payments totaling 100% of last year's tax liability, a taxpayer can ensure that no underpayment interest penalty will accrue, regardless of the current year's tax liability. Corporations that file the preceding year's return as an inactive corporation, or as a Subchapter S corporation, must submit 80% of the current year's tax liability in estimated payments if the $5,000 threshold is met.