U.S. stock markets went on a tear following the election and keep pushing into record territory. Proposed tax cuts and higher infrastructure spending should boost the economy, but also pile on the already high $20 trillion in U.S. federal debt.

For those looking, financial bubbles seem to be inflating everywhere. Student loans are approaching $1.3 trillion, with more than one in nine borrowers in default. In metro Denver, home price gains have outstripped incomes by a wide margin and high-end apartments are springing up everywhere.

But are these bubbles real and are any large enough to represent a danger?

“Bubbles are developing. But they are rational, and they are far from being in the bursting phase,” KC Mathews, chief investment officer at UMB Bank, told clients in Denver on Thursday.

One way to measure if U.S. stocks are overvalued is to look at the ratio of share prices to earnings per share. For the S&P 500, that ratio stands at 17.4, just a tad above the 25-year average of 17. Mathews said in periods of low interest rates and low unemployment, the ratio has run between 19 and 23. For reference, it reached 30 during the dot-com bubble.

Investors are banking on Trump administration promises, and consumer confidence has reached levels associated with faster economic growth. Lower corporate and individual tax rates, reduced regulation and higher infrastructure spending could boost earnings per share for S&P 500 companies by 16 percent, which supports higher stock values, Mathews said.

But efforts to boost the economy also are likely to elevate the already high, nearly $20 trillion in U.S. national debt, which stands at 105 percent of economic output.

Going above 90 percent is associated with economies able to grow no more than 2 percent annually. But of that debt, $5 trillion is held by the Federal Reserve, said Eric Kelley, UMB’s managing director of fixed income. That would suggest the burden isn’t as heavy as it might look.

And while a federal debt bubble is forming — and is projected to rise for years to come — the bursting point appears to be on the far horizon.

The U.S. economy last year grew around 1.6 percent and Mathews predicts it can hit 2.4 percent to 2.8 percent this year. The Trump administration will be hard-pressed to achieve the 4 percent growth rate it has targeted, he said.

Kelley said the fiscal stimulus and tax cuts, normally deployed at the start of a recovery, are coming late in the cycle, which reduces their impact. Higher interest rates, while necessary, will also weigh on growth.

Also, about half of GDP growth is tied to gains in the labor force, which is growing at a sluggish 0.7 percent. Drawing more people back into the workforce can help that, as can encouraging older workers to stay around longer.

The country needs to bring more working-age adults into the country if it wants to get the economy out of the 2 percent or lower growth rut it seems to be stuck in, Mathews said.

“We have to have a rationale, healthy immigration program or we will get dragged back,” Mathews warned on a day when immigration protests left restaurants and construction crews short staffed.