The US Treasury building in Washington. A key interest rate for the US financial system jumped to the highest level this year — exceeding the Federal Reserve’s target range — amid dwindling liquidity exacerbated by Treasury auction settlements and a quarterly corporate tax payment date. The Secured Overnight Financing Rate — a one-day lending benchmark linked to activity in the market for repurchase agreements — rose to 4.51% as of Sept. 15 from 4.42% the prior session, according to the latest Federal Re ...