"Six months since this turmoil started we still do not know how big the losses are," Charlie McCreevy, EU Commissioner for Internal Market and Services, said when addressing the Chartered Insurance Institute in London last week.
McCreevy warned little knowledge about the losses has undermined trust and confidence of investors and has caused serious disruption in certain markets, not least in the inter-bank markets.
"Without a clearer picture, restoring investor and business confidence will remain a significant challenge," he said.
Official figures showed confidence of European businesses and consumers has dropped below the long-term average, raising alarm to the momentum of investment and private consumption, the two growth engines.
In face of turmoil in financial markets, a sharp slowdown in the United States and soaring commodity prices, the European Commission last month revised down its economic forecast for the EU.
According to the commission, the EU economy will grow by 2 percent this year, slowing down from 2.9 percent in 2007.
Till now, the EU has not followed the United States to cut interest rate or take emergency measures like the 168-billion-dollar economic stimulus plan.
The European Commission president Jose Manuel Barroso said last month he saw no current need for emergency measures since the circumstances in Europe are not the same as those in the United States.
"If we hasten into knee-jerk measures, we will end up undermining the strong fundamentals on which our measured confidence is based," Barroso said.
Barroso said Europe must strive to deliver growth, jobs, low inflation and low interest rates consistently over time under the Lisbon Growth and Jobs Strategy.