There was recent case where a co-owner asked the IRS to assist in a battle with his partner. The company was behind in making its payroll tax payments. No surprises there, I am sure. The co-owner had a falling out with his partner; he discovered that the firm failed to pay all of its employment taxes.
He was so vexed invited an IRS agent to a board meeting where the partner was ousted from the business. This was the beginning of his defense. But in spite of the payroll tax liability, the co-owner wrote checks to himself, his wife and paid other liabilities, ignoring the IRS.
Now the executive may have brought in the IRS because of the payroll tax liability; he now knew of the outstanding liability. He may not have been responsible for the directly paying the employment taxes, but he was an officer, who owned at least half of the stock
As well as having check-signing authority. He’s liable for the unpaid tax
(Jenkins, Fed. Cir.).