The morning trade opened with a fall in the dollar exchange rate on the Russian currency market today. The high was only 29.915 rubles per dollar and the average-weighted dollar exchange rate was 29.91 rubles, which is 0.02 rubles less than the official dollar exchange rate set by the Central Bank for today. Specialists linked a drop in the dollar rate today to a significant ruble deficit of Russian commercial banks. A banking expert noted in an interview with RBC that problems with ruble liquidity started yesterday when one-day ruble credit rates reached 20 per cent. Later they dropped to about 5 or 10 per cent but jumped to 28-30 per cent in the morning today. The analyst could not name the reason for the current ruble deficit. He guessed it may be connected with a drop in the balance at correspondent accounts.