By the index calculation base is meant the list of bond issues (GKO/OFZ), used when calculating Indices of Russian government bonds and indicators of Russian government bonds' redemption yield.

The calculation base is re-calculated automatically monthly, that helps to take into account the changing situation in the GKO-OFZ market.

The following bond issues are not considered when determining the calculation base:

• bond issues used in Bank of Russia's sales of bonds with obligatory repurchase;
• bond issues with maturity less than 365 day as of the month's last day new calculation base is applied to.

The calculation base is comprised of bond issues, the liquidity indicator for which exceeds 1.

Liquidity indicator formula:

where:
V_i — average daily turnover of the i-th bond issue, in rubles;
T_i — average daily number of the i-th bond issue deals;
 — average daily turnover, calculated by the arithmetic mean formula on the basis of Vi for all bond issues considered, in rubles;
 — average daily number of deals, calculated by the arithmetic mean formula on the basis of Ti for all bond issues considered;
 — coefficients (0.2 and 0.8 correspondingly).

When calculating average daily turnover and average daily number of deals for the i-th bond issue, only those deals are taken into account, which are carried out on the secondary market on the basis of orders addressed to all market participants (anonymous trade mode).

• The Methodology of Calculation of Indices and Indicators
• The Methodology of determining the index calculation base
• Current calculation base