Stresses created by the low oil price are contributing to elevated credit risk in the US banking sector despite a relatively strong economy, regulators have warned. In a joint report US banking watchdogs said the value of weak loans nationwide had risen by 9.4 per cent from last year, while the value of loans that were heading towards trouble was up 18.5 per cent. Agency officials attributed the deterioration in large part to the troubled state of many oil and gas companies, which are straining under the pressure of a sub-$50 per barrel oil price. The total value of loans to oil producers and service companies is $276.5bn, or 7.1 per cent of the universe of big loans assessed jointly by three federal regulators in an annual review. Outside the oil and gas sector, the regulators said leveraged lending and loose underwriting were also increasing credit risk.