Heavy monsoon rain in and around India's financial capital, Mumbai (Bombay), is estimated to have caused damage worth 30bn rupees ($690m).
Others say the cost to agriculture and industry is likely to be much higher.
Indian officials say the number of people who have died could soon rise to 1,000. Rescue workers are still trying to recover bodies from flooded areas.
More than 20 million people have been affected by the rains, which began more than a week ago.
Meteorologists are still forecasting heavy rain and strong winds in the state of Maharashtra, of which Mumbai is the capital.
The heavy rain and accompanying floods have had a major impact on agricultural production and industry, analysts warn.
The Indian Merchants' Chamber estimates that the total damage thus far is 30 billion rupees ($690m), according to the Economic Times newspaper.
The Mumbai Chamber of Commerce and Industry has given a figure of 40 billion rupees ($888m).
But it says this figure only represents the tip of the iceberg.
"One has to do the assessment very carefully," says Abheek Barua, chairman of the Mumbai Chamber of Commerce and Industry.
"The chamber's estimate of damages at 40 billion rupees is only a ballpark figure. It will be much higher," the AFP news agency quotes him as saying.
Maharashtra is one of the largest producers of sugar and oilseeds, both major cash crops, and production is expected to take a big hit.
But it is also a big base for the pharmaceutical and automobile industries.
New rains will hamper the clean-up work in Mumbai
With many warehouses flooded, there are fears that any more rain could lead to a shortage of drugs.
The rains have also led to record-breaking insurance claims.
India's four biggest private insurers - ICICI Lombard General Insurance, Iffco-Tokio General Insurance, Bajaj Allianz General Insurance and Tata AIG General Insurance - have received claims for damages totalling 10bn rupees.
Last Tuesday Mumbai received more than 65cm (26in) of rain - the heaviest recorded in India's history, causing havoc in a city known for its inadequate infrastructure.
About half of those killed in Maharashtra have died in Mumbai - drowned, electrocuted or buried in landslides.
Rescue workers are still trying to recover bodies from flooded areas of Raigad district, 150 km south of Mumbai.
The district's senior administrator, Sanjay Yadav, said that more than 20 villages have been evacuated due to fears of fresh landslides.
Kalina is one of the worst affected areas of Mumbai
The spread of waterborne disease remains a major concern. Mumbai workers have sprayed insecticide to prevent malaria.
Non-governmental organisations are calling on the government to set up a centralised team to coordinate relief operations across the state.
About 200 medical teams have left Mumbai for affected towns and villages elsewhere in the state, while 30,000 health workers have been deployed in the city.
But hundreds of people are complaining that they have received insufficient help from the government.
They are taking shelter in temples and churches.
Sikander Zhaid, a resident of the Sanjay Nagar suburb in western Mumbai's Kalina district, told AFP that, "For the past seven days there has been no electricity nor drinking water. Taps are churning out muddy and filthy water."