Some 5,000 workers participated in a protest rally in the Greek capital as part of the 24 hour strike of Greece's largest labour unions. The strike disrupted services at airports, schools, hospitals, ports and banks. A Greek public prosecutor is investigating whether the civil servants' auxiliary pension fund was overcharged for a structured government bond, and findings are expected this month. Recent polls show the scandal over the sale of the overpriced bond to the pension fund has harmed the government's popularity, narrowing the gap between the governing conservative party and opposition Socialists. The government has banned pension funds from investing in bond derivatives while the investigation continues. Greek workers have already staged several protests this year over low wages and pensions as the government follows a tight fiscal policy praised by the European Union. The governing New Democracy party came to power in 2004 with a strong lead over the Socialist PASOK party.