The nonpartisan Congressional Budget Office said the cost of the shutdown would make the U.S. economy 0.02 percent smaller than expected in 2019. More significant effects will be felt by individual businesses and workers, particularly those who scrambled to make ends after not being paid.
Overall, the U.S. economy lost about $11 billion during the five-week period, the CBO said. It expects $8 billion to be recovered, however, as the government reopens and employees receive back pay.
"Among those who experienced the largest and most direct negative effects are federal workers who faced delayed compensation and private-sector entities that lost business. Some of those private-sector entities will never recoup that lost income," the report said.
The longest shutdown in U.S. history ended on Friday when Trump and Congress agreed to temporary government funding - without money for his U.S.-Mexico border wall - as the effects of the shutdown intensified across the country.
The Republican president had demanded that legislation to fund the government contain $5.7 billion for his long-promised wall. He says it is necessary to stop illegal immigration, human trafficking and drug smuggling, while Democrats call it costly and inefficient.
A committee of Republican and Democratic lawmakers have scheduled an initial meeting on Wednesday, which will be open to the public, as they try to negotiate a compromise on border security before the Feb. 15 deadline.
Trump said he would be willing to shut down the government again if lawmakers do not reach a deal he finds acceptable on border security. On Sunday, he expressed skepticism such a deal could be made.
Trump has also said he might declare a national emergency to get money for the border wall. Democrats would likely challenge that in court.