The units aren&#x27;t the same. The <i>shorthand</i> for the units is the same.<p>A dollar <i>of market cap</i> is very different from a dollar <i>of GDP</i>, like a cubic meter of lead is different from a cubic meter of air.<p>What we&#x27;re talking about is the value (or weight); the denomination (or volume) is irrelevant.<p>The value of a dollar GDP is considerably more tangible than a dollar market cap.