Despite a booming economy, many Americans are having trouble paying credit card bills, industry observers warn.

An increasing number of auto borrowers are also asking for more time to pay.

These trends disturb card industry experts.

“It is a problem we should watch,” says Bill Hardekopf, founder of LowCards.com.

“I would say that credit card defaults is definitely a cause for concern,” says Joe Resendiz, an analyst with ValuePenguin, which tracks the credit industry.

Resendiz noted the recent second-quarter net credit card default numbers rose for Bank of America and JPMorgan. In an otherwise rosy report, the amount of in-default charge card bills rose by 10 percent and 9 percent, respectively, compared with the same period in 2017.

But JPMorgan charge-off rates remain “low” on a historical basis, said spokeswoman Betty Riess.

The latest numbers also come at the same time that those with the poorest credit card records — subprime borrowers — saw their credit card debt increase by 26 percent, ValuePenguin said.

Another observer, LendingTree.com, noted a $16.25 billion increase in revolving debt in May. “This was the biggest May jump since 1995,” it said. Revolving debt is the card debt that is carried from month to month, usually at high interest rates because a card, unlike a house, is an unsecured debt.

Revolving and non-revolving debt is currently at $3.86 trillion, LendingTree said. It predicts it will pass $4 trillion this year.

Some borrowers, credit industry analysts say, are forgetting the disasters of 2008. That’s when a sudden recession left many Americans without jobs and big banks with huge unpaid debts.

Resendiz said most big banks are seeing default rates rise. The credit card default rate rose in the latest Federal Reserve numbers to 3.65 percent.

This was the seventh straight quarterly increase, yet still far from the 2008 numbers, when default rates were above 10 percent.