As the US crosses the $40 trillion mark it's easy to look at dollar signs but ratio to GDP is more relevant, writes Ian Verrender.

The federal government’s $1 trillion debt milestone comes at a risky time as interest rates on government debt hit multi-decade highs in global bond markets.

As the US crosses the $40 trillion mark it's easy to look at dollar signs but ratio to GDP is more relevant, writes Ian Verrender.