The Petroleum Fund's foreign exchange requirements are partly covered by the state's direct financial interest in petroleum activities (SDFI) and partly by Norges Bank's foreign exchange purchases in the market.

The Ministry of Finance establishes the amount of the monthly allocations to the Petroleum Fund. Norges Bank's purchases of foreign exchange are equal to the difference between the allocations and SDFI's estimated foreign exchange revenues. Adjustments will be made for any revisions of estimates for the previous month. As a result, the daily purchases may vary somewhat from one month to the next. The daily foreign exchange purchases are fixed for a period of one month at a time and are announced on the last business day of the preceding month.