Greek shipowners spent $1.7bn on newbuildings last month and topped the tally.
According to Clkarson Research Services, in January-May, they invested $5.3bn in new ship orders.
About 85% of the total orders were placed in April and May and if the trend continues, Greek could book more new orders this year than in 2010 in terms of value. CRS forecasts Greek order value could rise 2.7% year-on-year.
Greek owners have focuessed most of the investment on drillships and containerships rather than bulkers and tankers.
Meanwhile, during the first five months Norwegian owners booked $5.2bn newbuildings followed by Danish and German with $2bn and $1.8bn each.
US owners spent $7bn while Brazilian invested $4.6bn in newbuildings.
Global new ship orders came in at $39.6bn by May, compared to $96.2bn in the whole of 2010.