ATHENS — Giorgos Sofronas, 66, has run a small shop selling ladies’ bags in central Athens for more than four decades. This year, all of a sudden, the future became uncertain.

Mr. Sofronas has seen his sales drop by 45 percent since the onset of an unprecedented debt crisis earlier this year that prompted the Greek government to increase taxes and cut public salaries, in return for a €110 billion, or $154 billion, rescue package from its euro-zone partners and the International Monetary Fund. The measures have sliced profit margins at businesses large and small and damped consumer demand.

Watching shops closing one after another on his street has made Mr. Sofronas nervous, but he will not contemplate bankruptcy. “This business feeds nine people,” he said, referring to his family and five employees. “I can’t give up.”

In Greece, small businesses — defined as stores or workshops employing fewer than 10 people, though many are one-person operations — account for 96 percent of all enterprises and employ around two million of Greece’s five million-strong work force. Many small businesses, particularly in Athens and on Greece’s many islands, support the tourism sector, a crucial part of the economy that is also reeling from the repercussions of the debt crisis.