A Fed survey shows that banks are exceptionally reluctant to lend to large and medium-sized businesses and many companies cannot afford the present borrowing rates, which obstinately defy Greenspan's cuts. He is being frustrated by our old friend the yield curve, which measures how interest rates vary according to the length of the loan. Short-term rates, now that the official level is down to 1.75% are, of course, very cheap. But as you go up the curve, rates rise sharply. The 10-year Treasury Bond, which is the benchmark for so much business borrowing, is still being priced by the markets to yield over 5%.