The Athens stock market fell more than three percent early Tuesday after suffering a record fall of more than 16 percent on the first day of trading after a five-week shutdown.
Forty minutes into Tuesday's session, the ATHEX index was down 3.64 percent at 643.72 points after opening up 0.11 percent.
Monday's plunge of 16.32 percent to 668.06 points was its worst drop in nearly 30 years, highlighting investors' ongoing anxiety about the Greek economy even after a new rescue deal was agreed last month.
The previous worst loss in the stock market's history was a 15.03 percent tumble in 1987.
The reopening of the stock market came after senior EU and IMF auditors held their first meetings with Greek ministers to finalise a new three-year bailout for the country that could be worth up to 86 billion euros ($94 billion).
Uncertainty over the fate of Greece's economy, and its place in the eurozone, has seen bank customers withdraw some 40 billion euros ($44 billion) since December, leaving lenders dangerously low on cash and in need of urgent recapitalisation.