According to forecasts from the bank's chief economist, the federal deficit will increase from $825 billion (or 4.1 percent of gross domestic product) to $1.25 trillion (5.5 percent of GDP) by 2021. And by 2028, the bank expects the number to balloon to $2.05 trillion (7 percent of GDP).

"An expanding deficit and debt level is likely to put upward pressure on interest rates, expanding the deficit further," Jan Hatzius — Goldman's chief economist — wrote Sunday. "While we do not believe that the U.S. faces a risk to its ability to borrow or repay, the rising debt level could nevertheless have three consequences long before debt sustainability becomes a major obstacle."

Legislators passed a package of corporate and individual tax cuts in December, a two-year budget deal in February and a massive spending bill in March that boosted government expenditures on both domestic and military programs.