Earlier this week, before first JPM (JPM) and then Wells Fargo (WFC) revealed that not all is well when it comes to bank energy loan exposure, a small Tulsa-based lender, BOK Financial (BOKF), said that its fourth-quarter earnings would miss analysts’ expectations because its loan-loss provisions would be higher than expected as a result of a single unidentified energy-industry borrower. This is what the bank said:

“A single borrower reported steeper than expected production declines and higher lease operating expenses, leading to an impairment on the loan. In addition, as we noted at the start of the commodities downturn in late 2014, we expected credit migration in the energy portfolio throughout the cycle and an increased risk of loss if commodity prices did not recover to a normalized level within one year. As we are now into the second year of the downturn, during the fourth quarter we continued to see credit grade migration and increased impairment in our energy portfolio. The combination of factors necessitated a higher level of provision expense.”

Another bank, this time the far larger Regions Financial (RF), said its fourth-quarter charge-offs jumped $18 million from the prior quarter to $78 million, largely because of problems with a single unspecified energy borrower. More than one-quarter of Regions’ energy loans were classified as “criticized” at the end of the fourth quarter.

It didn’t stop there and and as the WSJ added, “It’s starting to spread” according to William Demchak, chief executive of PNC Financial Services Group Inc. (PNC) on a conference call after the bank’s earnings were announced. Credit issues from low energy prices are affecting “anybody who was in the game as the oil boom started,” he said. PNC said charge-offs rose in the fourth quarter from the prior quarter but didn’t specify whether that was due to issues in its relatively small $2.6 billion oil-and-gas portfolio.

Then, on Friday, U.S. Bancorp (USB) disclosed the specific level of reserves it holds against its $3.2 billion energy portfolio for the first time. “The reason we did that is that oil is under $30” said Andrew Cecere, the bank’s chief operating officer. What else will Bancorp disclose if oil drops below $20… or $10?

It wasn’t just the small or regional banks either: as we first reported, on Thursday JPMorgan (JPM) did something it hasn’t done in 22 quarters: its net loan loss reserve increased as a result of a jump in energy loss reserves. On the earnings call, Jamie Dimon said that while he is not worried about big oil companies, his bank has started to increase provisions against smaller energy firms.