US treasury bonds are a historically safe investment, safe as it comes. Assume for this analysis that US treasury bonds are still safe and nobody fears a government default. Then when the government has to promise to pay people more to loan it money this means people with money to loan see lots of good investment opportunities elsewhere because otherwise there'd be lots of demand for good ol' safe US bonds and that would bid up their price and consequently drive down their rate of return. This implies there's more demand for stocks, real estate, or whatever other investment. I'd assume this means people these days see lots of profitable investment opportunities.