Beginning in 2011, S-Corporations that file a late or incomplete Federal income tax return (Form 1120-S) will be assessed a penalty of $195 per shareholder per month. Husbands and wives are counted as two shareholders. For a 10-shareholder S-Corporation that is one year behind in filing its tax return, the penalty that may be imposed would be $23,400 (12 months x 10 shareholders x $195).