Two money market interventions by the US Federal Reserve in three working days are confirmation, if any were needed, that the credit markets remain sickly. Though the Fed is right to try, its latest action is unlikely to have much effect.

In addition to rate cuts, Fed intervention has escalated since it cut its discount rate last August. Last December it began offering $20bn of 28-day loans twice a month, it increased that to $30bn in January, and has now upped it to $50bn. Last Friday it announced another $100bn of term liquidity, so there will soon be a total of $200bn in longer-term Fed finance that was not on offer three months ago. It has not prevented another spike in the rate at which banks will lend to each other.