The information about the Federal Home Loan Bank of San Francisco (Bank) included in these unaudited financial statements reflects all adjustments that, in the opinion of the Bank, are necessary for a fair statement of results for the periods presented. These adjustments are of a recurring nature, unless otherwise disclosed. The results of operations in these interim statements are not necessarily indicative of the results to be expected for any subsequent period or for the entire year ending December 31, 2020. These unaudited financial statements should be read in conjunction with the Bank’s Annual Report on Form 10-K for the year ended December 31, 2019 (2019 Form 10‑K).

There have been no changes to the basis of presentation of the Bank’s financial instruments meeting netting requirements or of the Bank’s investments in variable interest entities disclosed in “Item 8. Financial Statements and Supplementary Data – Note 1 – Summary of Significant Accounting Policies” in the Bank’s 2019 Form 10-K.

Beginning January 1, 2020, the Bank adopted new accounting guidance related to the measurement of credit losses on financial instruments that requires a financial asset or group of financial assets measured at amortized cost to be presented at the net amount expected to be collected. The new guidance also requires credit losses relating to these financial instruments as well as available-for-sale (AFS) securities to be recorded through the allowance for credit losses. Key changes as compared to prior accounting guidance are detailed below. Consistent with the modified retrospective method of adoption, the prior period has not been revised to conform to the new basis of accounting. For information on the prior accounting treatment and for descriptions of the Bank’s significant accounting policies, see “Item 8. Financial Statements and Supplementary Data – Note 1 – Summary of Significant Accounting Policies” in the Bank’s 2019 Form 10-K. Other changes to these policies as of March 31, 2020, are discussed in Note 2 – Recently Issued and Adopted Accounting Guidance.

Use of Estimates. The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America (U.S. GAAP) requires management to make a number of judgments, estimates, and assumptions that may affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities, and the reported amounts of income, expenses, gains, and losses during the reporting period. The most significant of these estimates include:

Interest-bearing Deposits, Securities Purchased under Agreements to Resell, and Federal Funds Sold. The Bank invests in interest-bearing deposits, securities purchased under agreements to resell, and Federal funds sold. These investments provide short-term liquidity and are carried at cost. Accrued interest receivable is recorded separately on the Statements of Condition.

These investments are evaluated quarterly for expected credit losses. If applicable, an allowance for credit loss is recorded with a corresponding adjustment to the provision for/(reversal of) credit losses. The Bank treats securities

purchased under agreements to resell as collateralized financing arrangements because they effectively represent short-term loans to counterparties that are considered by the Bank to be of investment quality, which are classified as assets in the Statements of Condition. Securities purchased under agreements to resell are held in safekeeping in the name of the Bank by third-party custodians approved by the Bank. In accordance with the terms of these loans, if the market value of the underlying securities decreases below the market value required as collateral, the counterparty must place an equivalent amount of additional securities as collateral or remit an equivalent amount of cash. Consequently, a credit loss would be recognized if there is a collateral shortfall which the Bank does not believe the counterparty will replenish in accordance with its contractual terms. The credit loss would be limited to the difference between the fair value of the collateral and the investment’s cost. The Bank invests in Federal funds sold with counterparties that are considered by the Bank to be of investment quality.

Investment Securities. On a quarterly basis, the Bank evaluates its individual AFS investment securities in an unrealized loss position for impairment. A security is considered impaired when its fair value is less than its amortized cost basis. With respect to any debt security, a credit loss is defined as the amount by which the amortized cost basis exceeds the present value of the cash flows expected to be collected. If a credit loss exists but the entity does not intend to sell the debt security and it is not more likely than not that the entity will be required to sell the debt security before the anticipated recovery of its remaining amortized cost basis (the amortized cost basis less any current-period credit loss), an allowance for credit losses is recorded with a corresponding adjustment to the provision for/(reversal of) credit losses. The allowance is limited by the amount of the unrealized loss. Accrued interest receivable is recorded separately on the Statements of Condition. The allowance for credit losses excludes uncollectible accrued interest receivable, which is measured separately.

If management intends to sell an impaired security classified as AFS, or more likely than not will be required to sell the security before expected recovery of its amortized cost basis, any allowance for credit losses is written off and the amortized cost basis is written down to the security’s fair value at the reporting date with any incremental impairment reported in earnings as net unrealized gain/(loss) on AFS securities. If management does not intend to sell an impaired security classified as AFS and it is not more likely than not that management will be required to sell the debt security, then the credit portion of the difference is recognized as an allowance for credit losses and any remaining difference between the security’s fair value and amortized cost is recorded to net unrealized gain/(loss) on AFS securities within other comprehensive income/(loss).

Prior to January 1, 2020, credit losses were recorded as a direct write-down of the AFS security carrying value. For improvements in cash flows of AFS securities, interest income follows the recognition pattern pursuant to the impairment guidance in effect prior to January 1, 2020, and recoveries of amounts previously written off are recorded when received. AFS securities with a credit loss recognized pursuant to the impairment guidance in effect prior to January 1, 2020, continue to follow the prior accounting until maturity or disposition. For improvements in impaired AFS securities with an allowance for credit losses recognized after the adoption of the new guidance, the allowance for credit losses associated with recoveries may be derecognized up to its full amount. Effective January 1, 2020, the net non-credit-related other-than-temporary impairment (OTTI) gain/(loss) on AFS securities was reclassified to net unrealized gain/(loss) on AFS securities within other comprehensive income/(loss).

Held-to-maturity (HTM) securities are carried at cost, adjusted for periodic principal repayments, amortization of premiums and accretion of discounts, and previous credit loss recognized in net income and Accumulated Other Comprehensive Income (AOCI) recorded prior to January 1, 2020. On a quarterly basis, the Bank evaluates its HTM investment securities for expected credit losses on a pool basis unless an individual assessment is deemed necessary because the securities do not possess similar risk characteristics. If necessary, an allowance for credit losses is recorded with a corresponding adjustment to the provision for/(reversal of) credit losses. Prior to January 1, 2020, credit losses were recorded as a direct write-down of the HTM security carrying value. Accrued interest

For improvements in HTM securities impaired prior to January 1, 2020, interest income continues to follow the recognition pattern pursuant to the impairment guidance in effect prior to January 1, 2020, and recoveries of amounts previously written off are recorded when received. For improvements in impaired HTM securities with an allowance for credit losses recognized after the adoption of the new guidance, the allowance for credit losses associated with recoveries may be derecognized up to its full amount.

Advances. The Bank reports advances (loans to members, former members or their successors or housing associates) either at amortized cost or at fair value when the fair value option is elected. Advances carried at amortized cost are reported net of premiums, discounts (including discounts related to the Affordable Housing Program), and hedging adjustments. Accrued interest receivable is recorded separately on the Statements of Condition. The advances carried at amortized cost are evaluated quarterly for expected credit losses. If deemed necessary, an allowance for credit losses is recorded with a corresponding adjustment to the provision for/(reversal of) credit losses. See Note 4 – Advances for details on the allowance methodologies relating to advances.

Mortgage Loans Held for Portfolio. The Bank classifies mortgage loans as held for investment and, accordingly, reports them at their principal amount outstanding net of unamortized premiums, unamortized credit enhancement fees paid as a lump sum at the time loans are purchased, discounts, and unrealized gains and losses from loans initially classified as mortgage loan commitments. The Bank performs a quarterly assessment of its mortgage loans held for portfolio to estimate expected credit losses. An allowance for credit losses is recorded with a corresponding adjustment to the provision for/(reversal of) credit losses.

The Bank measures expected credit losses on mortgage loans on a collective basis, pooling loans with similar risk characteristics. If a mortgage loan no longer shares risk characteristics with other loans, it is removed from the pool and evaluated for expected credit losses on an individual basis.

When developing the allowance for credit losses, the Bank measures the estimated loss over the remaining life of a mortgage loan, which also considers how the Bank’s credit enhancements mitigate credit losses. The Bank includes estimates of expected recoveries within the allowance for credit losses. If a loan is purchased at a discount, the discount does not offset the allowance for credit losses. Accrued interest receivable is recorded separately on the Statements of Condition. The allowance excludes uncollectible accrued interest receivable, as the Bank writes off accrued interest receivable by reversing interest income if a mortgage loan is placed on nonaccrual status.

The Bank does not purchase mortgage loans with credit deterioration present at the time of purchase. See Note 5 – Mortgage Loans Held for Portfolio for details on the allowance methodologies relating to mortgage loans. For more information related to the Bank’s accounting policies for the Mortgage Partnership Finance® (MPF®) Program, see “Item 8. Financial Statements and Supplementary Data – Note 1 – Summary of Significant Accounting Policies” in the Bank’s 2019 Form 10-K. (“Mortgage Partnership Finance,” “MPF,” and “MPF Xtra” are registered trademarks of the FHLBank of Chicago.)