Old Second’s tax-equivalent net interest margin was 5.09% in the fourth quarter, up four basis points from the prior quarter and up 41 basis points from the year-ago period, management said. Eccher attributed margin performance in part to a decline in deposit costs and the company’s ongoing effort to reduce reliance on wholesale funding as higher-cost deposits reprice in a falling-rate environment.Chief Operating Officer and Chief Financial Officer Brad Adams said performance to close out the year was “pret ...