The weighted average exchange rate of  tenge against US dollar fixed on the stock exchange as of 15:30 Nur-Sultan time is set as an official exchange rate of the national currency tenge against US dollar for the next business day after the trading day. 
The exchange rate of tenge against other currencies is calculated through the cross rates fixed as of 16-00  Nur-Sultan time.

During the period from January 6, 2016 to February 1, 2016 market exchange rates and official exchange rates, set by the National Bank, varied in calculation methodologies. The market exchange rate was calculated as an average exchange rate of tenge against US dollar on the morning (main) trading session at the stock exchange (at 11:00 Almaty time), and recalculation against other currencies was conducted at 15.00. The official exchange rate was calculated as an average of both trading sessions (morning and afternoon at 15.30 Almaty time), recalculation against other currencies was conducted at 16.00.

Starting from February 2, 2016 calculation methodologies for the official and market exchange rates are identical. Therefore, the exchange rates file is generated according to the previous methodology, which was effective before January 6, 2016. An archive on the market exchange rates during the period from of January 6, 2016 to February 1, 2016, can be found at "Statistics" section - "Exchange rates" - "Daily currency market rates ( Archive)”.

In accordance with the Law of the Republic of Kazakhstan "On mass media" information on foreign exchange rates against tenge, published on the National Bank of Kazakhstan’s official internet-resource http://nationalbank.kz, is the National Bank of Kazakhstan’s official message and does not require additional written confirmation from the National Bank of Kazakhstan.