Ten Thousand Shares Is Half the Test: Rule 5320 Also Needs $100,000

Two desks send the same ticket on the same morning. One is 10,000 shares of a stock trading at $9.00, the other is 10,000 shares of a stock trading at $12.00. On the blotter the two lines are indistinguishable: same size, same side, same time in force. Under FINRA Rule 5320 (Prohibition Against Trading Ahead of Customer Orders) they are not the same ticket at all. One of them the firm holding it may trade alongside for its own account, on disclosure given in advance, and the other it may not. The dividing line is not the share count that both tickets share. It is a dollar figure, $100,000, and the two FINRA documents that publish that figure do not agree about which side of the line an order worth exactly $100,000 sits on.

What follows tracks that one number and nothing else. Not the history of Manning obligations, not the policy argument for carving large orders out of a customer-priority rule. Just $100,000: where it is printed, what it gets multiplied by, which way the boundary points, and how many order tickets in the whole penny-priced universe are actually caught in the disagreement. That last count is finite and small.

One Threshold, Two Published Wordings

Rule 5320(a) states the default, and it makes itself conditional in its first four words. The text filed with the Commission reads: “Except as provided herein, a member that accepts and holds an order in an equity security from its own customer or a customer of another broker-dealer without immediately executing the order is prohibited from trading that security on the same side of the market for its own account at a price that would satisfy the customer order, unless it immediately thereafter executes the customer order up to the size and at the same or better price at which it traded for its own account.” Hold a customer order, and the firm may not fill itself at a price that would have filled the customer unless the customer gets the same fill immediately after, except as provided herein. Paragraph (b) adds the supervisory half in two sentences: a member “must have a written methodology in place governing the execution and priority of all pending orders that is consistent with the requirements of this Rule and Rule 5310”, and “also must ensure that this methodology is consistently applied.” The supplementary material is not a gloss sitting outside (a). It is the “herein” that (a) defers to.

The exception that matters here lives in Supplementary Material .01, titled Large Orders and Institutional Account Exceptions. As filed, it reaches orders for customer accounts meeting the definition of an institutional account, or orders of “10,000 shares or more (unless such orders are less than $100,000 in value)”, and for those orders “a member is permitted to trade” on the same side of the market at a price that would satisfy the customer order. The rule grants a permission conditioned on disclosure; it does not speak of negotiating terms. The parenthetical is a carve-out from a carve-out: size gets the order into the exception, and the dollar figure can pull it back out. The trigger for pulling it back out is being “less than $100,000 in value”, so an order that is not less than that figure stays inside the exception.

Now read the same provision as FINRA itself summarised it when the consolidated rule went live. FINRA Regulatory Notice 11-24 (Consolidated FINRA Rulebook: Rule 5320) says that “Rule 5320.01 generally continues to permit firms to negotiate terms and conditions on the acceptance of certain large-sized orders (orders of 10,000 shares or more and greater than $100,000 in value) and orders from institutional accounts”. Same rule, same two figures, opposite boundary. The filed text excludes an order only when its value falls below $100,000. The notice requires the value to exceed $100,000. An order sitting on the figure is inside the exception under the first wording and outside it under the second.

The proposed text is available independently of the rulebook page, in SEC filing SR-FINRA-2009-090, Exhibit 5 (proposed Rule 5320 text). A third document tracks the filed wording rather than the notice wording: when the New York Stock Exchange retired NYSE Rule 92 and adopted its own NYSE Rule 5320 in 2011, the Federal Register notice of SR-NYSE-2011-43 (NYSE Rule 5320) described the carve-out in the filed form, as orders of 10,000 shares or more unless such orders are less than $100,000 in value. Two of the three read the boundary as inclusive. The odd one out is the document a compliance desk is likeliest to have read first.

Where the Two Readings Part Company

Multiply the share leg out and the disagreement gets a price tag. At $9.99 a share, 10,000 shares is worth $99,900. That is less than $100,000 on any reading, so a non-institutional order falls outside the exception and keeps the full Rule 5320 protection. At $10.01 a share, 10,000 shares is worth $100,100, which is both not-less-than and greater-than $100,000, so the order is inside the exception on both readings. Between those two prices there is exactly one penny, and in that penny sits $10.00, where 10,000 shares is worth $100,000 to the cent.

So the entire distance between the two published wordings, held at a fixed size of 10,000 shares, is one cent of price and $100 of notional. Hold the price fixed instead and the distance is one share: at $10.00, the filed text is satisfied by 10,000 shares, while the notice wording is not satisfied until 10,001 shares, worth $100,010. That is the whole of it. One share, or one cent, on one order shape.

Which reading governs is not a close question as a matter of hierarchy: the filed and approved rule text is the operative instrument, and a regulatory notice explains it. The trouble is that two systems inside one firm can disagree about the same ticket. An order-entry check built from the rule text lets it through; a supervisory exception report built from the notice flags it.

Concrete Framework

The test has two legs and they bind in different regions. Leg one is size: 10,000 shares or more. Leg two is value: the order must clear $100,000, with the boundary treated as inclusive if the filed text controls. For a non-institutional account both legs must be met, so the smallest qualifying order at a given price is the larger of the two requirements. Written out, the minimum qualifying size is 10,000 shares or the smallest whole number of shares whose value reaches $100,000, whichever is greater.

Run it across prices. At $1.00 the value leg demands 100,000 shares. At $2.00 it demands 50,000. At $4.00, 25,000. At $5.00, 20,000. At $8.00, 12,500. At $9.00 the arithmetic stops being round: $100,000 divided by $9.00 is 11,111.1 recurring, so 11,111 shares are worth $99,999 and the smallest qualifying size is 11,112 shares, worth $100,008. At $9.99 the same rounding gives 10,011 shares, worth $100,009.89, because 10,010 shares come to $99,999.90 and fall short by a dime. At $10.00 the two legs meet exactly at 10,000 shares. Above $10.00 the value leg goes quiet: 10,000 shares at $20.00 is $200,000, so the size leg is the only one still doing work.

That crossover is the practical content of the rule for anyone sizing orders. Below $10.00 a share, quoting the exception as a 10,000-share threshold is wrong in the direction that costs the customer protection. A 10,000-share order in a $3.00 name is a $30,000 order, nowhere near the value leg, and it keeps the full benefit of Rule 5320(a). Above $10.00 the shorthand happens to be right, which is why it survives on desks that trade higher-priced names and breaks on desks that do not. Mapping a share count onto notional before applying any size-based rule is the habit that prevents this, the same habit behind the 144-Tick Journal note on mapping hundred-share units into notional.

The Thirteen Order Shapes on the Seam

The two readings can only disagree when an order lands on $100,000 exactly. Everywhere else, the order is either under the figure, in which case both wordings exclude it, or over it, in which case both wordings admit it. So the population of genuinely disputed tickets is the set of orders whose value is precisely $100,000 and whose size is at least 10,000 shares. That set can be counted, on one assumption the documents obtained here do not settle: that the value is read off a single price attached to the ticket. Neither document says which price that is.

Restrict attention to whole shares and to prices quoted in whole cents at or above $1.00. Write the price as a number of cents. The order value is exactly $100,000 when the share count equals 10,000,000 divided by that number of cents, and the share count has to come out as a whole number, so the price in cents has to divide 10,000,000 without remainder. It also has to be at least 100 cents, to stay at or above a dollar, and at most 1,000 cents, because the quotient has to reach 10,000 shares to clear the size leg. The divisors of 10,000,000 in that window are 100, 125, 128, 160, 200, 250, 320, 400, 500, 625, 640, 800 and 1,000 cents. Thirteen of them.

Laid out as tickets, the thirteen are 100,000 shares at $1.00, 80,000 at $1.25, 78,125 at $1.28, 62,500 at $1.60, 50,000 at $2.00, 40,000 at $2.50, 31,250 at $3.20, 25,000 at $4.00, 20,000 at $5.00, 16,000 at $6.25, 15,625 at $6.40, 12,500 at $8.00 and 10,000 at $10.00. Each multiplies out to $100,000 to the cent; 78,125 times $1.28 and 15,625 times $6.40 are the two least obvious rows.

Above $10.00 the seam closes for a structural reason, not a numerical accident. Any order of 10,000 shares or more priced above $10.00 is worth more than $100,000 and clears the value leg under either wording, while an order worth exactly $100,000 priced above $10.00 would need fewer than 10,000 shares and fails the size leg before the value question arises. The disagreement lives entirely in the low-priced end of the tape, which is also where share-count conventions do the most damage to intuition about size, as in the 144-Tick Journal piece on an odd lot that prints, adds to volume, and does not set the last sale.

What an Institutional Account Does to the Same Test

Both legs can be bypassed altogether. Supplementary Material .01 reaches institutional accounts as an alternative to the size-and-value route, and FINRA Rule 4512 (Customer Account Information) supplies the definition. Paragraph (c) covers a bank, savings and loan association, insurance company or registered investment company; a registered investment adviser; and “any other person (whether a natural person, corporation, partnership, trust or otherwise) with total assets of at least $50 million”. The third branch is the one that does the work in practice, and its threshold is a balance-sheet figure rather than an order figure.

Set the two routes side by side and the intuition about size inverts. A 500-share order from an account with $50 million in total assets is eligible for the exception, because the account qualifies and size is irrelevant on that branch. A 10,000-share order in a $9.00 stock from a retail account is not eligible, because it clears the size leg and misses the value leg at $90,000. The larger ticket is the protected one. Anyone who has internalised the exception as a rule about big orders has the case backwards whenever the counterparty is institutional and the order is small.

Eligibility is also not self-executing. The permission runs only “provided that the member has provided clear and comprehensive written disclosure to such customer at account opening and annually thereafter” that both discloses the proprietary trading and “provides the customer with a meaningful opportunity to opt in to the Rule 5320 protections” as to all or any portion of the order. In lieu of the written route, a member may give clear and comprehensive oral disclosure and take consent order by order, documenting who consented. So an order can sit past both numeric legs and still carry full Rule 5320 protection, because the disclosure behind the account was not in place, or because the customer opted in.

What the Desk Should Do With One Share

The operational answer is short. Code the value leg to the filed rule text, treating the figure as met when the order value reaches it, and then make the seam disappear by not sitting on it. An order that comes in at the exact figure is one share or one cent away from being uncontroversial in either direction. Size it to 10,001 shares and it is inside the exception on both wordings; take one share off and it is outside on both. The only expensive choice is to leave it exactly where it is and let two internal systems argue.

The second thing worth doing is checking which wording each internal document inherited. A written methodology under Rule 5320(b) that paraphrases the threshold as greater than the figure gets the outcome right everywhere but the thirteen, and paraphrases of a parenthetical are how the seam opened. Quoting the parenthetical costs nothing and removes the ambiguity from the one ticket where it bites.

What Would Invalidate This

The continuous text of Supplementary Material .01 was not retrieved in full for this piece. The retrieval layer returned it in fragments, and the sources file records exactly which fragments were captured verbatim and where each one breaks off. The parenthetical at the centre of the argument is confirmed twice over, in the Commission filing of the proposed text and on the rulebook page, and the notice wording is confirmed twice over, in the notice web page and in the notice as circulated. The surrounding disclosure conditions are quoted only from the fragments that were captured whole.

Which price the value leg is computed from was not settled by the documents obtained here. A limit price on the ticket, the prevailing market at the moment of receipt, and the eventual execution price can all differ, and for an order near the figure that choice decides the outcome more often than the inclusive-versus-exclusive question does. Anyone relying on the thirteen-ticket count should read the supplementary material in full and any interpretive guidance attached to it before treating the count as complete.

Three further conditions would break the count. Prices below $1.00 are quoted in increments finer than a cent, so admitting them enlarges the set well past thirteen; the count holds only for whole-cent prices at or above a dollar. Fractional share quantities would do the same. And the seam is a drafting artefact, so it closes the moment either document is revised: a reissued notice that tracks the filed parenthetical, or an amendment to the filed text that adopts the notice wording, ends the disagreement without changing a single number. NYSE Rule 5320 sits in a separate rulebook and was adopted as substantially the same rule rather than an identical one, so its own supplementary material should be read on its own terms before the same arithmetic is carried across to it.