Private bondholders must accept a bond swap with Greece by Thursday night or risk a disorderly default that may spread to Italy and Spain. The markets tumbled to a sharply lower open with the Dow plunging 168 points to 12,793 while Nasdaq plummeted 47 points to 2902.

On the upside

XOMA (Nasdaq: XOMA) will raise approximately $39.2 million through a public offering of more than 29 million common shares.

Monster Worldwide (NYSE: MWW) retained the services of Stone Key Partners and Bank of America Merrill Lynch to explore strategic alternatives.

VeriFone Systems (NYSE: PAY) reported a loss for the first quarter but the results were better than expected and the company forecast full year results ahead of estimates.

On the downside

Oncothyreon (Nasdaq: ONTY) widened fourth quarter losses more than expected and warned of higher expenses in 2012.

Investors locked in profits on Keryx Biopharmaceuticals (Nasdaq: KERX) and AEterna Zentaris (Nasdaq: AEZS) whose shares surged yesterday.

NutriSystem (NYSE: NTRI) disappointed by falling to a greater than expected loss for the fourth quarter as revenue tumbled and warned of losses for the current quarter.

In the broad market, declining issues outpaced advancers by a margin of more than 11 to 1 on the NYSE and by nearly 6 to 1 on Nasdaq. The Russell 2000 which tracks small cap stocks tumbled 11 points to 792.