System Open Market Account (SOMA)

The account is a portfolio framework, not a retail bank account, whose securities and other positions support central-bank operations rather than household saving or a commercial investment mandate, so a business cannot open a SOMA account to obtain financing. The New York Fed's holdings information identifies Treasury securities, agency debt and agency mortgage-backed securities in the domestic portfolio, so describing it as only Treasury bonds misses other important asset categories.

The foreign portfolio has a different currency and investment context. Policy and execution have different owners, as the Federal Open Market Committee sets policy instructions while the New York Fed's desk carries out relevant transactions and is not simply choosing securities to maximise profit like an independent private fund manager.

Purchases can increase the central bank's asset holdings and supply reserves through settlement, while sales, maturities and principal repayments can reduce holdings depending on whether proceeds are reinvested. The balance-sheet effect depends on the transaction and the wider operating framework.

A declining portfolio does not require selling every security in the market, since allowing principal to mature or repay without full reinvestment is another route, which matters when interpreting announcements about balance-sheet reduction. Treasuries and mortgage-backed securities do not run off in identical ways, because a Treasury security has contractual maturity dates while mortgage-backed principal payments also reflect the underlying loans, including prepayments.

The pace can therefore depend on borrower behaviour and interest rates. The Federal Reserve's accounting manual describes how domestic SOMA holdings and related results are participated among Reserve Banks, so a portfolio executed centrally can appear through allocated shares in individual Reserve Bank accounts, and those shares should not be counted again as separate new purchases.

Accounting measures also need interpretation, since face value, amortised cost and market value answer different questions about the same securities, and adding figures from different measurement bases can produce a misleading portfolio total. Foreign-currency positions introduce exchange-rate effects, and the accounting manual describes daily revaluation of foreign-currency investments and associated gains or losses, so a change in dollar-reported value need not mean the desk bought or sold the same amount of foreign assets.

SOMA is narrower than the whole Federal Reserve balance sheet, because other assets and liabilities can arise from different facilities and operations, so a headline portfolio total should not be described as every form of central-bank support to the financial system. For a business reader, changes in the portfolio provide monetary-policy context rather than a direct borrowing quote, and they can affect market conditions, but a company's loan price also depends on credit risk, lender terms and the relevant market.

A holdings chart does not promise a specific mortgage or deposit rate. Use dated official holdings and policy instructions when making comparisons, identifying the asset category, valuation basis and observation date.

Separating purchases, reinvestment, runoff and valuation changes gives a clearer explanation than calling every portfolio movement money printing or tightening.