The costs of the deadly storm in Texas and the Gulf of Mexico continued to mount on Thursday, with some analysts estimating losses that approach $100bn.
Harvey has killed more than 30 people and destroyed thousands of homes.
Many firms in the region, a major transport hub that is a home to the oil and gas industry, don't know when they will resume normal operations.
Risk Management Solutions, which works with insurance companies, estimates direct losses could reach $90bn.
Moody's Analytics has estimated damage at about $75bn, but the figures could rise.
While the rain has shifted away from Houston, many parts of the city remain underwater.
"The flood waters haven't receded yet, so it's very difficult to know what exactly the damage is," said Tom Sabbatelli, senior product manager for RSM.
Harvey, which started as a hurricane, dumped unprecedented rainfall on America's fourth largest city and one of the country's major economic engines.
The storm struck at the heart of America's oil and gas industry, knocking a fifth of all US production offline, closing refineries around the Gulf Coast, and causing major pipelines that move fuel to other markets to shut.
Petrol prices, which increased in anticipation of the storm, are expected to continue to rise, despite additional shipments from overseas. In Texas, shortages at stations in some areas have been reported.
Mansfield Oil Company, a wholesale gas supplier, is trying to bolster its supplies by bringing in fuel by lorry, rail - even ships, depending on the market.
He said getting the Houston-area refineries back up will be key.
"We're all struggling," he said. "It's going to be a situation we're going to be dealing with for a few weeks."Image copyright AFP/Getty Image caption More than a fifth of US oil refining capacity has been affected.
Companies are trying to figure out when they can restart operations.
Colonial Pipeline said it expects to re-open its Houston line by Sunday, but other firms said they don't know when normal operations might resume.
"Given the unprecedented flooding in the city of Port Arthur, it remains uncertain how quickly the flood waters will recede, so we cannot provide a timeline for restart at this time," said Motiva, which runs one of the biggest refineries. "Our priority remains the safety of our employees and community."
Has there been major damage?
Moody's expects costs to businesses to total $10bn-$15bn, with additional infrastructure costs rising as high as $10bn.
Some damage was already evident.
Fires from organic peroxides were reported at the Crosby plant of chemical company Arkema and more were expected, after flooding overwhelmed the firm's back-up generators and refrigerators designed to keep the materials cool failed.
The plant was six feet underwater, the company said.Image copyright AFP/Getty Image caption Flooded houses after Hurricane Harvey hit Rockport, Texas on August 26, 2017.
Shutdowns of other facilities have led to releases of pollutants, while water has overwhelmed Houston's sewers. The structural integrity of reservoirs are also being monitored, the White House said.
Up and running?
Partial service has resumed at Houston airports and the port is expected to open for limited business on Friday, but parts of the Houston Ship Channel, which provides access to refineries, remain off-limits.
Other transit networks may take longer as roads and other land remains submerged.
Railroad BNSF, for example, has suspended trains that would have travelled through the region and warned they would not resume for "an extended period".
"I don't even want to speculate," BNSF spokesman Joe Faust said.
The majority of the damage has been felt by families, who are likely to be grappling with the financial hit without insurance.
More than 350,000 people have registered for assistance from the federal government, said FEMA.
More than 37,000 people have also filed claims to the National Flood Insurance Program by mid-Thursday.
Analysts say they expect that number to rise to about 500,000.Image copyright AFP/Getty Image caption People sort through donated clothes at the Lake Charles Civic Center in Lake Charles, Louisiana on August 31, 2017.
But many of the losses will not be covered, which is likely to make it harder for families - and the economy - to bounce back, analysts said.
"A lack of flood insurance for homeowners will prevent the type of full-scale reconstruction effort that might otherwise be expected," Moody' s wrote. "This could have significant long-term ramifications."
How will this affect the economy?
The Houston region is responsible for more than $500bn in economic activity annually.
AccuWeather expects the storm to shave a full percentage point off GDP over 12 months and lead the Federal Reserve to hold off on raising interest rates.
Macroeconomic Advisers is forecasting that lower production as a result of the storm could reduce third quarter GDP by 0.3% -1.2%, depending on how long the recovery takes.
But senior economist Ben Herzon says money spent on reconstruction should help boost the figures in later months.
He's hopeful that the impact will fall on the smaller end of the scale.
"I think the economy tends to be very robust and maybe even more robust than is sometimes expected," he said.