Think of bank earnings as a thermometer.

Regional banks take the temperature of local economies, and big banks do the same for the country as a whole.

Nathan Stovall at S&P Global Market Intelligence said that when JPMorgan Chase, Wells Fargo and Citigroup report their financial results Friday, he’ll be looking at deposits and loan portfolios.

“Are they becoming less willing to lend because they’re worried about where we are in the economic cycle?” he asked, adding that he looks for reports of borrowers falling behind on loans, especially commercial real estate loans.

“Is it business as usual? Are they preparing for stress?” he said. “Are they clamoring for more deposits?”

March saw a pair of bank failures, near the end of the first quarter, which will make these second-quarter reports especially interesting.

“It was hard to see exactly all those effects play out from just Q1,” said Steven Kelly at the Yale Program on Financial Stability. “So we’ll see a full quarter of sort of post-crisis bank activity, and that will give us a good sense of how things have changed inside banks since then.”

How they’re doing financially and also how they’re reading the economy. But there’s still plenty that earnings reports don’t reveal. Case in point: those failed banks.

“So I just went for fun to see the last two earnings reports of First Republic Bank,” said Anat Admati, a finance professor at the Stanford Graduate School of Business. “If you looked at them in January, their quarter four report, things were great. Completely great. I mean, everything was up, everything was wonderful.”

But by late April, First Republic’s first-quarter earnings report wasn’t so rosy, and the bank collapsed a week later.