HTM vs. AFS Securities: Bank Investment Portfolio Classifications

Introduction

Banks hold large portfolios of investment securities (primarily government bonds and agency mortgage-backed securities) for liquidity management, interest rate risk hedging, and yield generation. How a bank classifies these securities on its balance sheet has profound implications for reported equity, regulatory capital, and management flexibility. The distinction between Held-to-Maturity (HTM) and Available-for-Sale (AFS) is one of the most important accounting concepts in bank analysis, and it became a central topic in FIG after the 2023 banking crisis demonstrated how classification choices can mask enormous unrealized losses.

For FIG bankers, understanding HTM vs. AFS is essential for analyzing bank balance sheets, assessing interest rate risk exposure, and evaluating the true economic capital position in M&A due diligence.

Under ASC 320 (the US GAAP standard for investment securities), banks classify debt securities into three categories at the time of purchase:

Held-to-Maturity (HTM): Securities the bank has the positive intent and ability to hold until maturity. HTM securities are carried at amortized cost on the balance sheet. Unrealized gains and losses (the difference between amortized cost and fair market value) are disclosed in the footnotes but do not flow through the income statement or equity. The key advantage is balance sheet stability: rising interest rates do not reduce reported book value. The key constraint is liquidity: if a bank sells more than an insignificant amount of its HTM portfolio before maturity, it may be forced to reclassify the entire HTM portfolio as AFS, triggering immediate mark-to-market recognition.

Available-for-Sale (AFS): Securities that the bank may sell before maturity but does not actively trade. AFS securities are carried at fair value on the balance sheet. Unrealized gains and losses flow through Other Comprehensive Income (OCI) and accumulate in Accumulated Other Comprehensive Income (AOCI) within shareholders' equity. AFS unrealized losses reduce reported book value but do not flow through the income statement (unless the security is impaired). AFS provides more flexibility than HTM because the bank can sell securities without triggering a reclassification event.

Trading Securities: Securities held for short-term trading purposes. Carried at fair value with unrealized gains and losses recognized directly in the income statement. Trading securities are primarily held by large broker-dealers and capital markets-oriented banks and are less relevant for traditional commercial bank analysis.

Held-to-Maturity (HTM) Securities

Debt securities that a bank has the positive intent and ability to hold until maturity, carried at amortized cost on the balance sheet. Because HTM securities are not marked to market, unrealized gains and losses from interest rate movements do not affect reported equity or (for most banks) regulatory capital ratios. This creates accounting stability but can mask economic reality: a bank may report strong book value while sitting on billions in unrealized losses that would be realized if the securities had to be sold. The SVB crisis of 2023 highlighted this risk, as Silicon Valley Bank's HTM portfolio contained approximately $15 billion in unrealized losses (over 90% of total equity) that were not visible on the face of the balance sheet.

The choice between HTM and AFS classification is one of the most consequential accounting decisions a bank's treasury team makes. Once securities are placed in HTM, management sacrifices liquidity flexibility in exchange for balance sheet stability. The following table summarizes the key differences across all three categories.

When interest rates rise, the fair value of existing fixed-rate bonds falls (bond math: higher rates mean lower present values of fixed cash flows). This creates unrealized losses on the investment portfolio. How those losses are recognized depends entirely on classification:

For AFS securities, unrealized losses flow through AOCI and reduce reported book value. A bank with a $50 billion AFS portfolio that declines $5 billion in value sees its equity decrease by $5 billion (pre-tax). This is economically transparent: the balance sheet reflects the true market value of the securities.

For HTM securities, the same $5 billion unrealized loss is disclosed in footnotes but has zero impact on reported book value or equity. The balance sheet looks the same as if rates had not moved. This is the source of both the appeal and the danger of HTM classification.

Silicon Valley Bank's failure in March 2023 is the definitive case study for HTM risk. SVB had accumulated a massive HTM portfolio during 2020-2021 when it invested surplus deposits (from tech and venture capital clients) into long-duration agency mortgage-backed securities and US Treasuries at historically low yields. As of March 2022, HTM securities represented approximately 46% of SVB's total assets.

When the Federal Reserve began raising interest rates aggressively in 2022, the fair value of SVB's HTM portfolio declined dramatically. By year-end 2022, SVB's HTM securities had approximately $15 billion in unrealized losses, representing over 90% of the bank's total equity. These losses were disclosed in footnotes but did not appear on the face of the balance sheet.

When deposit outflows accelerated in early March 2023, SVB was forced to sell $21 billion of AFS securities at a $1.8 billion realized loss. The market immediately questioned the remaining HTM portfolio, and a classic bank run ensued. SVB failed within 48 hours of its loss announcement.

The regulatory treatment of AFS unrealized gains and losses adds another layer of complexity. Under Basel III as implemented in the US, there is an AOCI opt-out available to all banks except the largest "advanced approach" institutions (roughly the 22 largest US banks). Banks that elect this opt-out can exclude AFS unrealized gains and losses from their regulatory capital calculations, meaning that rising rates and falling bond values do not reduce their CET1 ratios.

The largest banks (JPMorgan, Bank of America, Wells Fargo, Goldman Sachs, Morgan Stanley, and others using the advanced approach) do not have this opt-out. Their AFS unrealized losses flow through to regulatory capital, which incentivizes them to classify more securities as HTM (where losses are invisible to both equity and capital ratios).

The international framework is fundamentally different. Under IFRS 9, which governs European and most non-US banks, debt securities are classified based on the bank's business model and the contractual cash flow characteristics of the instrument. The three IFRS 9 categories (amortized cost, fair value through OCI, and fair value through profit or loss) produce similar outcomes to HTM, AFS, and trading respectively, but the classification criteria are more principles-based. Importantly, European regulators generally do not offer an AOCI opt-out, meaning AFS unrealized losses flow through to CET1 capital for all European banks, not just the largest. This difference affects cross-border bank comparisons: a European bank and a US regional bank with identical portfolios and identical unrealized losses will report different capital ratios because the European bank includes the losses in CET1 while the US bank (if it elected the opt-out) does not.

In bank acquisitions, the investment securities portfolio is a key due diligence focus. The acquirer's FIG advisors analyze:

The SVB crisis permanently changed how FIG analysts approach the investment securities portfolio. Adjusted TBV, HTM footnote scrutiny, and interest rate sensitivity analysis of the securities book are now standard elements of both ongoing bank coverage and M&A due diligence.