The five-week partial shutdown of the U.S. government will ultimately cost the world's biggest economy just $3 billion, though the closure had indirect effects that are tough to measure, the Congressional Budget Office (CBO) said.

The impasse delayed about $18 billion in federal discretionary spending, the non-partisan arm of Congress said Monday in a report on the shutdown. As a result, the annualized rate of fourth-quarter gross domestic product growth (GDP) is expected to be 0.2 percentage point lower than anticipated, while expansion in the first three months of the year will be 0.4 percentage point weaker, it said.

However, the CBO said most of the lost output “will eventually be recovered,” with second-quarter growth expected to bounce back. The net drop in GDP for the calendar year will amount to $3 billion, or 0.02 percent of annual output, the agency said.