B-1 STATEMENT OF ADDITIONAL INFORMATION Dated May 1 ...

CALCULATION OF YIELD QUOTATIONS OF THE MONEY MARKET PORTFOLIOThe Money Market Portfolio’s yield is its current investment income expressed in annualized terms.The Portfolio’s yield is calculated by determining the net change in the value of a pre-existing accounthaving a balance of one share at the beginning of a seven-day base period. The net change in the value ofthe account is divided by the value of the account at the beginning of the period to obtain the base periodreturn. The result is then multiplied by 365 and divided by seven, with the resulting annualized yieldcarried to the nearest hundredth of one percent. For purposes of this calculation the net change in thevalue of the account reflects the value of additional Portfolio shares purchased with dividends from theoriginal share and dividends declared on both the original share and any such additional shares. Thecalculation reflects net investment income of the Portfolio for the period, including accrued interestincome plus or minus amortized purchase discount or premium, less all accrued expenses, but does notinclude realized or unrealized gains or losses.FINANCIAL STATEMENTSThe financial statements, related notes and related report of PricewaterhouseCoopers LLP,independent registered public accounting firm, contained in the Annual Report to Shareholders of theFund as of December 31, 2008 and for the year then ended are hereby incorporated by reference. Copiesof the Fund’s Annual Report or, when it becomes available, Semi-Annual Report as of, and for the sixmonths ending, June 30, 2009 (unaudited) may be obtained without charge by writing to TheNorthwestern Mutual Life Insurance Company, 720 East Wisconsin Avenue, Milwaukee, Wisconsin53202, by calling (414) 271-1444, or by visiting the website at www.nmfn.com.B-65