The typhoons hit the manufacturing base in the main island of Luzon very hard. The capital island provides three fifths of the country's GDP.
From Reuters, reporters Rosemarie Francisco and Karen Lema give us more details from the study.
Damages and losses to crops, property, and infrastructure from typhoons Ketsana and Parma reached nearly $4.4 billion, or 2.7 percent of the Southeast Asian country's gross domestic product, according to the post-disaster needs assessment report issued by the World Bank.
The total is well above the $823 million estimate of Manila's disaster agency, which only accounted for direct damages and excluded resulting economic and property losses.
"The disaster is expected to have a negative impact on GDP growth in the short term," said the report, which was done in collaboration with other international donors and the Philippines government.
"However, once projected public and private recovery and reconstruction spending are included, the net impact of the disasters on economic activity is expected to result in real GDP growth of 1.0 percent in 2009 and 3.5 percent in 2010."
The World Bank estimates are within the government's forecasts of growth hitting the low end of its target range of 0.8 to 1.8 percent this year and picking up to 2.6-3.6 percent in 2010.
Finance Secretary Margarito Teves said the multilateral lenders had offered to extend around $3 billion worth of grants, concessional and commercial loans to the Philippines, but he raised concern that the money may not arrive in time.