A mark to market adjustment is the accounting entry that updates an asset or liability on the balance sheet to reflect its current market value, with the change recorded as an unrealized gain or loss. Buy a stock at $50, watch it close at $52, and the $2 increase is the adjustment, booked as an unrealized gain even though you have not sold a share. The mechanic keeps financial statements tied to current economic reality rather than to stale purchase prices, and the same idea drives daily cash settlement in futures accounts and a specific tax election available to active traders.
How the Calculation Works
The math is simple. Take the current fair value of the asset, subtract the previous carrying value on the balance sheet, and the difference is the adjustment. Hold 1,000 shares carried at $50 and the market closes at $52, and the balance sheet value moves from $50,000 to $52,000, producing a $2,000 unrealized gain. If the price drops to $48, you record a $2,000 unrealized loss. The word “unrealized” is doing real work here. You still own the asset, so the gain or loss is economic reality on paper, not cash in hand.
Fair value under modern accounting standards is defined as an “exit price”: the amount you would receive selling the asset in an orderly transaction between willing participants at the measurement date. That number can drift a long way from what you originally paid. A bond bought at par during a low-rate period may have a much lower exit price once rates climb, and the mark to market adjustment captures that shift. Historical cost accounting would keep carrying the bond at its original price adjusted only for scheduled amortization. Simpler, yes, but it can hide large latent losses.
Where observable market prices exist, the standards require you to use them without adjustment. Quoted prices in active markets for identical assets sit at the top of the fair value hierarchy. Where prices for the exact instrument are not available, valuation moves to observable inputs for similar assets, and only where those fail does it drop into unobservable inputs based on the entity’s own assumptions.1IFRS Foundation. IFRS 13 Fair Value Measurement That last category, often called Level 3, is where measurement uncertainty is highest and where footnote disclosures deserve the closest reading.
Where the Adjustment Shows Up in the Financial Statements
The balance sheet always reflects the updated fair value. What varies is where the unrealized gain or loss lands.
Trading Securities and Equity Investments
Debt securities classified as “trading” are measured at fair value, and unrealized gains and losses flow straight into net income. A broker-dealer with a large trading book will see those daily adjustments show up in trading revenue, which is why reported earnings for these firms swing sharply with markets.
Since 2018, most equity securities with readily determinable fair values follow the same treatment. Under FASB Topic 321, changes in the fair value of equity investments flow through net income each reporting period regardless of whether the entity considers them trading positions.2Financial Accounting Standards Board. Accounting Standards Update 2020-01, Investments – Equity Securities (Topic 321) The old available-for-sale category for equities is gone. A company holding publicly traded stock will see its reported earnings move with the share price even if it has no intention of selling.
Available-for-Sale Debt Securities
Debt securities classified as available-for-sale get different treatment. The balance sheet still reflects fair value, but unrealized gains and losses bypass the income statement and are parked in a separate equity account called Other Comprehensive Income. The adjustment accumulates there until the security is sold, at which point the gain or loss recycles into the income statement as a realized amount. The approach dampens income statement volatility for bonds a company does not plan to trade actively, while still giving balance sheet readers a current market value.
Realized Versus Unrealized
The distinction is straightforward. An unrealized gain or loss is the mark to market adjustment itself: value has changed, but you still hold the asset. A realized gain or loss occurs when you sell, and the final amount is the difference between the sale price and your original cost basis. If you have been marking the asset to market all along, the last adjustment before sale should be small, because the carrying value already sits close to the sale price. Over the full holding period, cumulative mark to market adjustments roughly equal the total realized gain or loss at sale.
Daily Cash Settlement in Futures Accounts
Mark to market is not only a reporting exercise. In futures trading, it is a daily cash event. Every trading day, the exchange publishes a settlement price for each contract, and your account is credited or debited based on how that price moved. Go long a crude oil futures contract, watch the settlement rise by $1 per barrel on a 1,000-barrel contract, and $1,000 lands in your account that evening. If it falls by $1, $1,000 is pulled out. This happens whether or not you close the trade.
The daily settlement is designed to keep losses from compounding to the point where a trader cannot pay. When you open a position you post initial margin as collateral. The daily adjustments then raise or lower your equity, and if losses push equity below the maintenance margin level, you receive a margin call requiring a deposit to restore the initial margin amount. Failing to meet the call gives the exchange or broker the right to liquidate your position.3CME Group. Margin: Know What’s Needed
Each morning starts clean. The prior day’s gains and losses have already been transferred, and the contract’s value resets to the settlement price. That is a fundamentally different rhythm from holding a stock, where unrealized gains and losses sit on paper until you sell.
What Gets Marked to Market
Mark to market is not universal. Some industries and asset classes face mandatory requirements; others can opt in.
Financial Institutions
Broker-dealers and investment companies face the most pervasive requirements. Virtually all of their investment holdings and proprietary positions are valued at fair value daily for both regulatory reporting and capital purposes. Commercial banks mark their trading books to market, though loan portfolios and held-to-maturity investments are typically carried at amortized cost. The line between what gets marked and what does not is where much of the risk hides.
Derivatives and Variation Margin
All derivative financial instruments must generally be measured at fair value, regardless of industry or purpose. Futures, options, and swaps all require continuous revaluation. For centrally cleared derivatives, the daily adjustment triggers variation margin: cash exchanged between counterparties each day to reflect the change in the contract’s market value. That is distinct from initial margin, which is the upfront collateral posted when the position opens and stays relatively stable. Variation margin flows back and forth daily so that neither side accumulates a dangerous amount of uncollateralized exposure.4FINRA. FINRA Rule 4210 – Margin Requirements
Even when a derivative is designated as a hedging instrument, its fair value is recorded on the balance sheet. Hedge accounting rules change where the unrealized gain or loss is recognized, not whether the adjustment happens.
Crypto Assets
For fiscal years beginning after December 15, 2024, FASB requires certain crypto assets to be measured at fair value with changes recognized in net income each reporting period. Under ASU 2023-08, this applies to fungible, blockchain-based digital assets that meet the definition of an intangible asset and do not give the holder enforceable rights to underlying goods or services. Bitcoin and ether are the obvious examples. Under the prior rules, crypto was carried as an indefinite-lived intangible asset under the impairment model, meaning values could be written down but never back up absent a sale.5Financial Accounting Standards Board. FASB Issues Standard to Improve the Accounting for and Disclosure of Certain Crypto Assets
The Fair Value Option
Under both U.S. GAAP and IFRS, an entity can voluntarily elect the Fair Value Option for financial instruments that would otherwise sit at amortized cost. A bank might elect this for a loan portfolio it hedges with derivatives, so both sides of the hedge are valued the same way and accounting mismatches shrink. The election is irrevocable once made for a specific instrument, so the income statement volatility it invites needs weighing before opting in.
Why It Matters: The Silicon Valley Bank Illustration
Mark to market can feel abstract until it triggers a crisis. Silicon Valley Bank’s collapse in March 2023 is one of the clearest examples of how the classification choice ripples into real-world consequences.
During the low-rate years before 2022, SVB invested heavily in long-term U.S. Treasury bonds and agency mortgage-backed securities, classifying most of them as held-to-maturity. Under that classification the bonds were carried at amortized cost, not fair value, so rising rates never touched the reported balance sheet values. Economic reality was different. As the Federal Reserve raised rates from 0.25% in March 2022 to 4.5% by December 2022, the market value of those bonds fell hard. By year-end 2022, SVB’s unrealized losses on held-to-maturity securities reached roughly $15.2 billion, and its available-for-sale portfolio showed another $2.5 billion in unrealized losses. Total unrealized losses amounted to roughly 110% of the bank’s capital.6Board of Governors of the Federal Reserve System. Material Loss Review of Silicon Valley Bank
When depositors began withdrawing funds and SVB needed cash, it sold $21 billion of available-for-sale bonds at a $1.8 billion realized loss. The announcement triggered a bank run. Had the entire bond portfolio been marked to market on the balance sheet, the deterioration would have been visible to regulators and depositors much earlier. The held-to-maturity classification legally shielded those bonds from mark to market adjustments, and it hid the risk. As of mid-2025, the median U.S. bank still carried net unrealized losses equal to roughly 10.5% of its Tier 1 capital.7Federal Reserve Bank of St. Louis. What Are the Characteristics of Banks with Large Unrealized Losses?
Mark to Market as a Tax Election
Mark to market also names a tax accounting method under Section 475 of the Internal Revenue Code, and it works very differently from the financial reporting version. For most investors, gains and losses on securities are capital gains and losses. The Section 475 election converts them to ordinary income and ordinary loss, which can save active traders significant money in a bad year.
Who Qualifies
Section 475(a) makes mark to market mandatory for securities dealers. The elective version under Section 475(f) is available to taxpayers who qualify as “traders in securities,” a narrower group than the label suggests. The IRS looks at factors such as trading frequency, typical holding period, the time devoted to trading, and whether trading provides a substantial portion of income.8Internal Revenue Service. Topic No. 429, Traders in Securities There is no bright-line test. Someone who places a few hundred trades a year while working a full-time job probably does not qualify; someone who trades daily as a primary occupation likely does.
How It Changes the Tax Treatment
Under the election, all securities held in connection with the trading business are treated as if sold at fair market value on the last business day of the tax year. The resulting gains and losses are classified as ordinary rather than capital.9Office of the Law Revision Counsel. 26 USC 475 – Mark to Market Accounting Method for Dealers in Securities
The ordinary loss classification is the main attraction. Without the election, net capital losses can only offset up to $3,000 of other income per year, with the rest carried forward.10Internal Revenue Service. Topic No. 409, Capital Gains and Losses With the election, a trader carrying a $100,000 net loss can deduct the full amount against salary, business income, or any other ordinary income in the same year. The trade-off is that gains also become ordinary income taxed at marginal rates rather than at long-term capital gains rates. For most active traders whose holding periods are short, gains would have been short-term capital gains taxed at ordinary rates anyway, so the practical cost is small.
The election also removes the wash sale problem. Normally, selling at a loss and repurchasing a substantially identical security within 30 days disallows the loss. The IRS has confirmed that the wash sale rules do not apply to traders using the mark to market method of accounting.8Internal Revenue Service. Topic No. 429, Traders in Securities
How and When to Elect
A qualifying trader makes the Section 475(f) election by attaching a written statement to the tax return, or extension request, by the original due date of the return for the year before the election takes effect. For the 2026 tax year, the statement must be filed by April 15, 2026, attached to the 2025 return or extension request. Extensions of time to file do not extend this deadline. Filing an e-return in October without having attached the election statement to a timely April extension means the election has been missed. Once made, it applies to the tax year for which it is filed and to all subsequent years unless the IRS consents to revocation. A change from a prior accounting method to mark to market may also require filing Form 3115.11Internal Revenue Service. Instructions for Form 3115
Tax MTM and Financial Reporting MTM Are Separate
The Section 475 election is completely separate from the mark to market requirements imposed by accounting standards. A broker-dealer is required to use MTM for its financial statements under GAAP regardless of any tax election, and the firm’s individual traders and principals must still file their own Section 475(f) elections to get ordinary loss treatment on their personal returns. Financial reporting MTM is a regulatory requirement driven by accounting standards. Tax MTM is an elective choice under the Internal Revenue Code. One does not automatically trigger the other.