Description:Standard and Poor's placed a negative credit watch on 15 members of the euro zone, citing systemic stresses in recent weeks, that of course due to the spreading two-year debt crisis. S&P says tightening credit conditions, higher risk premiums on sovereign debt and political wrangling within the euro zone are the other reasons. Negative credit watch means the countries could see a lower debt rating within 90 days of the warning.(1:58)