Extending a U.S. company tax return to October 15 with Form 7004: How do late-filing penalties for Forms 1120 and 5472 work?

For U.S. calendar-year corporations that filed Form 7004 for an extension, the filing deadline for Form 1120 is October 15, and Form 7004 extends the filing deadline but not the time to pay taxes. Late Form 1120 filings are generally penalized 5% of the unpaid tax per month, up to 25%, with an additional 0.5% monthly penalty on unpaid taxes and interest accruing from April 15. Failure to file a required Form 5472 carries a $25,000 penalty per form; if the form is not filed within 90 days, an additional $25,000 penalty applies for every 30 days of continued noncompliance, with no limit.