LONDON—Governments will benefit from the biggest inflation-driven drop in debt ratios in over 20 years, credit rating firm Fitch said on Wednesday, estimating it will slice around 5 percentage points off U.S. debt-to-GDP and 2 percentage points globally. The effects on government debt ratios from 2022 inflation vary by region, with the smallest impact being forecast for the Middle East & North Africa, and the largest impact in sub-Saharan Africa. Developed market sovereigns, in which inflation is forecast to push government debt ratios much lower than the median, include the United States at 5 percentage points of GDP, Britain at 4.6 percentage points and Canada at 4.1 percentage points. Averaged out across all 120 countries Fitch rates, the drop is set be 2 percentage points, matching 2008 for the most significant inflationary effect in more than 20 years. “It would be a stretch to claim that debt is being ‘inflated …