Short-term interest rates are rising again, making it costlier for investors and businesses to borrow when financial markets already are on edge.

After hovering around 2.3% for most of the spring and summer, the three-month London interbank offered rate, or Libor, has been climbing since the middle of September, settling at 2.52% on Friday The Wall Street Journal reported. Libor measures the cost for banks to lend to one another for short periods of time and is used as a benchmark for a range of interest rates, including those on margin debt and many corporate loans.