But in the past few months, business has jumped, not because the Greek economy is finally recovering but because it is falling even deeper into the abyss.

With the Greek government pushing through more tax increases to comply with austerity requirements, more than 21,000 self-employed workers and small firms have shut down in the past two months, with many seeking help from accountants like Mr. Tsamopoulos to close their books. Yet many are not actually closing their businesses.

"Most of these people will keep working," Mr. Tsamopoulous said, arching an eyebrow from behind his desk as clients waited in a smoky room outside. "But now, they'll do it on the black market. They're saying they need a way to survive."