Marking the close

Marking the close is trading in the final minutes of a session specifically to move the closing price, which is the price that sets portfolio valuations, margin calls, index levels and derivative settlements.

Also called painting the close, closing price manipulation. Observed in equities, futures, options, bonds. One of the order-book manipulation techniques. 10 enforcement actions in the library.
Updated 2026-09-07

How does marking the close work?

Marking the close exploits a structural feature of finance: one moment in the day is treated as authoritative, and everything else is treated as noise.

Prices move all session. Only one of them gets recorded as the price. That number flows into fund valuations, performance reports, management fees, margin calculations, index levels, covenant tests and derivative settlements. Someone whose payoff depends on any of those has a reason to care about a single print far more than about the trading that preceded it.

The mechanic requires no sophistication.

1. Identify a payoff that depends on the close. A month-end fund valuation, an option strike, a margin threshold, a covenant level, an index inclusion cut-off.

2. Wait until the last few minutes. Liquidity thins as the session ends in continuous markets, and the number of participants able to respond falls.

3. Buy or sell aggressively into the close. Enough to move the printed price in the required direction. In a liquid name this is expensive; in a thinly traded one it can be startlingly cheap.

4. Collect the benefit elsewhere. The trading itself usually loses money — the trader has bought at prices they pushed up. The profit is in the valuation, the fee, the settlement or the avoided margin call.

That last point is the diagnostic feature of the whole technique. In spoofing, the profit is in the trade. In marking the close, the trade is a cost, and the profit is somewhere else entirely. When you find someone reliably losing money in the closing minutes, ask what else they own.

A worked example with real numbers

A fund holds 900,000 shares of a small-cap stock that has traded between $12.37 and $12.42 all month. The fund’s management fee is 1.5% of assets, calculated on the month-end mark, and the manager also earns 20% of gains above a high-water mark.

On the final trading day, the stock is at $12.40 with 20 minutes to go. Typical closing-period volume is around 15,000 shares.

The manager has overpaid relative to the day’s earlier prices by roughly $13,000 — a real trading loss. Now look at the valuation effect on the existing 900,000-share position:

Mark at $12.40   900,000 × $12.40  =  $11,160,000
Mark at $12.94   900,000 × $12.94  =  $11,646,000
Increase in reported assets        =     $486,000

The reported value of the holding rose by $486,000 for a trading cost of $13,000. If the fund’s month-end mark drives a fee, drives a performance figure sent to investors, or determines whether a performance fee crystallises, that ratio is the entire motive.

And the position was never sold. The next morning the price will drift back toward $12.40, because nothing about the company changed. What survives is the number in the report.

Why is marking the close illegal?

Marking the close is a case of open-market manipulation: every individual transaction is real, executed at risk, and lawful in isolation. What makes the course of conduct unlawful is its purpose — to produce a printed price that does not reflect genuine supply and demand, so that the price can be used to mislead someone downstream.

In securities, Exchange Act § 9(a)(2) is the direct provision: effecting transactions that raise or depress the price of a security for the purpose of inducing others to buy or sell. Where the downstream deception is of investors in a fund rather than of other traders, § 10(b) and Rule 10b-5 do the work, because the misleading mark is a deceptive act in connection with the purchase or sale of securities.

Where the person marking the close manages other people’s money, the Investment Advisers Act adds a separate and often more serious charge. Section 206 prohibits fraud by an adviser on its clients, and inflating a mark that determines the adviser’s own fee is close to a paradigm case of it. Many marking-the-close actions are charged this way rather than as market manipulation, because the harm is to identifiable clients rather than to the market at large.

In commodities and futures, CFTC Rule 180.1 and the price manipulation provisions apply, and the conduct is generally described as banging the close where it targets a settlement window.

FINRA Rule 2020 and exchange rules give self-regulatory bodies an independent route against member firms, which is why a marking-the-close matter at a broker-dealer often produces a FINRA action before any government one.

The doctrinal difficulty is worth naming plainly. Courts have not settled how far intent alone can render facially legitimate open-market trades manipulative. Some decisions hold that lawful trades cannot become unlawful purely because of the trader’s purpose; others hold that manipulative intent is exactly what the statute targets. The practical consequence is that these cases are brought most readily where there is a separate deception — a false report to investors, a misstated valuation — rather than on the trading alone.

Which real enforcement actions have alleged marking the close?

This library holds 10 enforcement actions tagged marking the close. The table shows the largest by civil penalty together with the most recently filed. Every row links to a page carrying the regulator's own release and, where one was published, the complaint.

All 10marking the closeactions →

How does marking the close get detected?

Closing-period participation share. Surveillance computes each account’s share of volume in the final minutes and compares it to its share through the rest of the session. Legitimate closing activity from index funds is large but is also predictable and disclosed. An account that is absent all day and dominant at the close is anomalous.

Calendar clustering. The strongest single signal. Aggregate an account’s closing-period aggression by date and ask whether it concentrates on month-ends, quarter-ends, option expiries or index rebalance dates. A strategy that appears only on valuation dates is not a strategy.

Reversal analysis. Compare the closing price to the next session’s opening price. Trades that moved the close and were reversed the following morning did not reflect a durable view.

Economic interest mapping. Regulators identify what the trader owned that depended on the close — option positions, fund holdings, fee arrangements, covenant exposure — and test whether the direction of the closing trades matched the direction that interest required.

Loss-making pattern detection. Because the trading leg typically loses money, an account that consistently and specifically loses money in the closing minutes is a strong lead.

• Order flow concentrated in the closing minutes that is disproportionate to the account's activity through the rest of the session.
• Closing-period buying that recurs on month-end and quarter-end dates and is absent otherwise.
• Trading that pushes the close above a round number, an index inclusion threshold, an option strike or a covenant level.
• Positions or compensation that depend on the closing mark, held by the same person directing the closing trades.
• Aggressive orders into the closing auction that are reversed at the next open.

What penalties does marking the close actually attract?

The numbers below are computed from this site's own case records at build time, not quoted from a secondary source. They change whenever a new action is added to the library.

What are the red flags?

• A price that is flat all session and moves sharply in the last few minutes without news.
• Performance that appears reliably on the last trading day of a reporting period.
• A fund whose reported returns are consistently better than the intraday price path would imply.
• Closing prices that repeatedly settle just above a strike, a threshold or a covenant trigger.

For an investor in a fund, the observable version is a mismatch between reported returns and the intraday price path of the fund’s disclosed holdings — performance that appears on the last day of periods and does not persist into the next one.

For a compliance function, the useful control is a calendar-aware one: flag closing-period aggression by any account whose compensation, valuation or derivative exposure references the close, and require a written rationale for period-end closing trades that exceed a share of the auction.

What marking the close is not

It is not index tracking. Index funds must trade at the close, in size, to match their benchmark. This is the largest source of closing volume in equity markets and is entirely legitimate.

It is not closing auction participation. Auctions exist to concentrate liquidity at the close. Submitting to them is what they are for.

It is not any late-day price move. News arrives late in the day, positions are squared before weekends, and thin closing books move on ordinary flow. The case is built on repetition tied to dates that matter, not on a single sharp close.

Frequently asked questions about marking the close

What techniques are related to marking the close?

• Banging the close — Banging the close is trading heavily during the short window used to calculate a settlement price, in order to move that settlement in favour of a much larger position that references it.
• Marking the open — Marking the open is trading into a market's opening auction or first minutes to move the official opening price, which is thinner and cheaper to influence than the close but still feeds benchmarks and guarantees.
• Settlement price manipulation — Settlement price manipulation is trading to move an official settlement price, because that price determines margin, portfolio marks and the payoff on contracts many times larger than the trading itself.
• Options expiry pinning — Options expiry pinning is trading to hold a share price at or across an option strike at expiry, exploiting the fact that a few cents of movement decides whether large positions pay out or expire worthless.
• Painting the tape — Painting the tape is executing a series of transactions to create a misleading appearance of activity or of a price trend on the public trade record, in order to draw other participants in.

Terms defined on this page

Closing Auction · Settlement Price · Mark To Market · Net Asset Value · Vwap · Open Market Manipulation

Sources

1. Securities Exchange Act § 9 — Cornell Legal Information Institute
2. Investment Advisers Act § 206 — prohibited transactions by advisers — Cornell Legal Information Institute
3. FINRA Rule 2020 — use of manipulative, deceptive or other fraudulent devices — FINRA
4. SEC Rule 10b-5 — Electronic Code of Federal Regulations

Reviewed September 7, 2026. Every statute link points at the primary text. If something here is wrong, tell us — corrections are logged in public.