Been awhile since I employed anyone in America (that whole "we're going to annex you" thing) but if I had to hazard a guess, it's the company's portion of their FICA taxes? The company withholds the employee portion to remit to the IRS, then matches it dollar to dollar. If the company is structured so that Andrew is self-employed, it'd be SECA instead and you can count that portion as a business expense.