# EDGAR Filing Document

**Accession Number:** 0001798802
**File Stem:** 0001798802-25-000010
**Filing Date:** 2025-9
**Character Count:** 98502
**Document Hash:** 73bedbbc1009f88ef729ae8476f8cb25
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001798802-25-000010.hdr.sgml**: 20250905

**ACCESSION NUMBER**: 0001798802-25-000010

**CONFORMED SUBMISSION TYPE**: ATS-N/UA

**PUBLIC DOCUMENT COUNT**: 5

**FILED AS OF DATE**: 20250904

**DATE AS OF CHANGE**: 20250905

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** PURESTREAM, LLC
- **CENTRAL INDEX KEY:** 0001798802

**ORGANIZATION NAME:**
- **EIN:** 843426414
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** ATS-N/UA
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 013-00182
- **FILM NUMBER:** 251295208

**BUSINESS ADDRESS:**
- **STREET 1:** 75 ROCKEFELLER PLAZA
- **STREET 2:** STE. 2900A
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019
- **BUSINESS PHONE:** 201-694-6421

**MAIL ADDRESS:**
- **STREET 1:** 75 ROCKEFELLER PLAZA
- **STREET 2:** STE. 2900A
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10019

### Attached PDF Documents

**Attachment 1:** `Schedule_A.pdf`

_No text found in this document._

**Attachment 2:** `Schedule_B_2023.10.06.pdf`

_No text found in this document._

**Attachment 3:** `ex3_20250904.pdf`

_No text found in this document._

**Attachment 4:** `20250904_part3itm7a.pdf`

_No text found in this document._

## Form ATS-N/UA: NMS Stock Alternative Trading System Report

### Cover Page

**NMS Stock ATS Name:** PureStream, LLC

**Operates Pursuant to Form ATS?** —

**Statement About Amendment:**
PureStream, LLC is filing this Updating Amendment to its Material Amendment filed on August 6, 2025, to include: (i) a new maximum LTR applicable to LS orders (3,000%). This change is in Part III, Item 7 (Order Types and Attributes) with conforming changes in Part III, Item 11 (Trading Services, Facilities and Rules); and (ii) the introduction of a new customization feature around self-matching. With this customization, in addition to self-match prevention, Subscribers will also be able to elect to have its orders match only with other orders it has sent to the ATS (self-match only). This change is in Part III, Item 14 (Counter-Party Selection) with conforming changes in Part III, Item 11 (Trading Services, Facilities and Rules).

These changes apply to all Subscribers. These changes do not apply to the Broker-Dealer Operator because the Broker-Dealer Operator does not trade on the platform.

### Part I: Basic Information

**1. Is the ATS operated by a registered broker-dealer?:** Yes

**2. Name of the NMS Stock ATS:** PURESTREAM, LLC

**4a. Broker-Dealer SEC File No.:** 008-70472

**4a. Broker-Dealer CRD No.:** 000306750

**5a. Self-Regulatory Organization:** Financial Industry Regulatory Authority, Inc.

**5b. Effective Date of Membership:** 03/15/2021

**5c. MPID:** PURE

**6u. Website:** www.purestream.tech

**7. Primary Site Address:** Equinix NY4 Data Center, 755 Secaucus Road, Secaucus, US-NJ, 07094

**7. Secondary Site Address:** Equinix NY4 Data Center, 755 Secaucus Road, Secaucus, US-NJ, 07094

**8. Is Exhibit 1 (list of subscribers) on a public website?:** No

**9. Is Exhibit 2 (written standards for access) on a public website?:** No

### Part II: Written Safeguards and Procedures

**1a. Are any business units of the Broker-Dealer Operator permitted to enter interest?** —

**1b. Are the services offered and provided by the ATS to such business units the same?** —

**1c. Are there any arrangements between the ATS and such business unit?** —

**1d. Can order and trading interest of the business unit be routed out of the ATS?** No

**2a. Are any Affiliates of the Broker-Dealer Operator permitted to enter interest?** —

**2b. Are the services offered and provided by the ATS to such Affiliates the same?** —

**2c. Are there any arrangements between the ATS and such Affiliate?** —

**2d. Can order and trading interest of the Affiliate be routed out of the ATS?** No

**3a. Can a Subscriber opt-out from interacting with the order and trading interest of the Broker-Dealer Operator?** —

**3b. Can a Subscriber opt-out from interacting with the order and trading interest of an Affiliate?** —

**3c. Are the means to opt-out the same for all Subscribers?** —

**4a. Are there any arrangements between the Broker-Dealer Operator and a trading center?** No

**5a. Does the Broker-Dealer Operator offer any products or services to Subscribers?** —

**5b. Are the terms and conditions of these products/services the same for all Subscribers?** —

**5c. Does an Affiliate of the Broker-Dealer Operator offer any products or services to Subscribers?** —

**5d. Are the terms and conditions of these products/services offered by the Affiliate the same for all Subscribers?** —

**6a. Do any employees of the Broker-Dealer Operator or its Affiliates access confidential trading information?** Yes

   - **Details:** PureStream, LLC ("PURE") is the broker-dealer operator of the PureStream ATS (the "ATS" or "PURE ATS"). PURE ATS's confidential Subscriber information includes, but is not limited to, Subscriber order and trade information (e.g., symbol, side, quantity, price, type,), counter-parties, and billing instructions (collectively, the "Subscriber Confidential Information").

PureStream Trading Technologies Inc. ("PTT") is the parent company of PURE. PTT is not an operational business but is a holding company, and the owner of the intellectual property used in the PURE ATS. Further, PTT owns and manages the licensing of the order types available in the PURE ATS.

All PTT employees are shared personnel with PURE ("Shared Personnel") (i.e., there are no PTT employees that do not also service PURE).  Shared Personnel perform dual functions, with a primary role of supporting PURE and a secondary role of supporting PTT.  Shared Personnel include, for example, PURE's management, legal, finance and accounting, and support teams.  Shared Personnel generally function in a similar or equivalent capacity at PTT as they do at PURE (e.g., PURE management also serves as PTT management; and PURE legal personnel perform legal responsibilities at PTT).  Shared Personnel have Subscriber Confidential Information (see Part II, Item 7) in connection with their roles at PURE and they may also use such information in connection with their role at PTT, if needed.  All Shared Personnel are subject to the written safeguards and written procedures to protect Subscriber Confidential Information described in Part II, Item 7, and are not permitted to use Subscriber Confidential Information that they have access to for unauthorized purposes.

**6b. Does any other entity provide services to the ATS?** Yes

   - **Providers:** As noted above, PTT owns and manages the licensing of the order types available in the PURE ATS, and Shared Personnel have access to all Subscriber Confidential Information.

PURE has also entered into an agreement with Operations and Compliance Network, LLC ("Ocean"), an affiliate of Nasdaq, pursuant to which Ocean hosts, operates, and supports the ATS technology platform. Pursuant to this agreement, Ocean provides certain support services related to PURE's compliance, surveillance, supervisory, record-keeping, and reporting obligations. Ocean performs all of these services subject to the direction and oversight of PURE as the Broker-Dealer Operator.

Pursuant to the agreement with Ocean, certain aspects of the services provided by Ocean to PURE utilize infrastructure and support services shared by Ocean and its affiliates. As the Broker-Dealer Operator, PURE is responsible for the operation of the ATS in compliance with the federal securities laws. In addition to the tools provided by Ocean, PURE will monitor orders and transactions in real-time via ATS drop copies into PURE's infrastructure.

With respect to the applicable Item numbers in Part III of this form, PURE is responsible for:

Items 1, 2, and 3 - Subscriber eligibility.
Items 7, 8, 9, 13, and 14 - Market structure design.
Items 4 and 20 - Business decisions regarding the hours of operation, and closing of the market due to technical or operational risks.
Item 19 - Fees.
Item 22 - Clearance and Settlement (Via the ATS's clearing firm, Instinet, LLC ("Instinet"), a member of the National Securities Clearing Corporation ("NSCC").
Item 26 - Aggregate platform data.

With respect to the applicable Item numbers in Part III of this form, Ocean provides the infrastructure and support services for the following items, subject to the direction and oversight of PURE as the Broker-Dealer Operator of the ATS:

Item 5 - Financial Information eXchange ("FIX") connectivity to Subscribers.
Item 10, 17, and 20 - The technical process of opening and closing of the ATS for regular hours, and in the event a system stoppage (e.g., for a regulatory trading halt, a triggered market-wide circuit breaker, or for an internal reason) is triggered.
Item 11 - Daily management of the ATS, including all the hardware and systems required for the operation of the ATS.
Item 15 - Display.
Item 18 - Trading outside of regular trading hours.
Item 21 - Trade reporting (done via an outsourcing arrangement with S3, discussed below in Part II, Item 7).
Item 23 - Ocean provides Securities Information Processor ("SIP") feed handler software (CTA and UTP) that enables the ATS to consume market data.

One additional entity supports the ATS services in connection with the following Item:

Item 22 - PURE has an agreement with Instinet to act on behalf of the PURE ATS to clear and settle all Subscriber transactions executed on the ATS. Pursuant to such agreement, Instinet receives all ATS transactions and submits all executions to the NSCC for clearing.

The following items do not apply to the PURE ATS:
Item 6 - Co-location.
Item 12 - Liquidity providers.
Item 16 - Routing.
Item 24 - Order display and execution access.
Item 25 - Fair access.

**6c. Do any of these service providers also use the services of the ATS?** Yes

   - **Details:** Instinet, the ATS's clearing broker, is a Subscriber to the ATS and may submit trading interest to the PURE ATS. Instinet may use any of the PURE ATS functionality disclosed in this Form ATS-N.

**6d. Are the services of the ATS to such service provider the same as for other similar Subscribers?** —

**7a. Description of Safeguards and Procedures:**
PURE ATS's Subscriber Confidential Information includes, but is not limited to, Subscriber order and trade information (e.g., symbol, side, quantity, price, type,), counter-parties, and billing instructions, as described in Part II, Item 6.

PURE has established and maintains written policies and procedures designed to safeguard Subscriber Confidential Information. Pursuant to those procedures, the CEO grants access to Subscriber Confidential Information as needed to enable employees to perform their duties and responsibilities. PURE employees with access to Subscriber Confidential Information are strictly prohibited from using such information in an unauthorized manner, including discussing Subscriber Confidential Information with any persons not involved in the operation of the ATS or responsible for the ATS's compliance with applicable rules.

At present, given (i) the number of employees at PURE; (ii) the scope of employee roles; and (iii) that the ATS is the only product offered by PURE, the CEO, in consultation with the CCO, has granted all employees access to all Subscriber Confidential Information, on either a real-time or post hoc basis. As the number of employees at PURE increases, PURE's written policies and procedures will be amended to provide for more tiered or selective access to Subscriber Confidential Information.

Employees access the Subscriber Confidential Information primarily through PUMA (PureStream Monitoring and Analytics), PURE's proprietary application that is used in connection with trade monitoring, compliance obligations, and billing. Please see the response to Part II, Item 7.d below for additional information on the individuals and systems with access to Subscriber Confidential Information, including the basis for such access.

SEPARATION OF SYSTEMS AND PERSONNEL

The PURE ATS matching engine is hosted and operated by Ocean and is physically separate from the other PURE systems with access to Subscriber Confidential Information (e.g., PUMA). Similarly, the ATS matching engine and order entry servers are on separate hardware from other systems hosted and operated by Ocean. Additionally, the Ocean employees that are responsible for the daily operation of the ATS and that have access to the ATS's order book are in a separate physical location from PURE employees.

PURE is an agency only broker-dealer that exclusively operates the ATS and has no other lines of business or trading capabilities.

THIRD PARTY ACCESS PROTECTIONS:

Certain Ocean employees have access to Subscriber Confidential Information, including real-time and historical information regarding individual orders and executions, names of Subscribers, and volume of orders in the ATS. Such employees include Ocean staff from Compliance, Operations, Technology Development (including trading and surrounding systems), Product Management, and Business Management.

Ocean's policies and procedures (i) restrict which Ocean employees have access to Subscriber Confidential Information, and (ii) implement information barriers that prohibit employees with Subscriber Confidential Information from sharing such information in an unauthorized fashion, as well as (iii) impose personal trading limitations.

Ocean's policies and procedures employ a three-pronged approach to permission access to the PURE ATS. First, an Ocean employee must complete Compliance training specific to the Ocean business unit. Second, an Ocean employee must request, and Ocean Compliance must approve, access to each specific system based on the employee's designated role and responsibilities where such role and responsibilities require access to the PURE ATS. No other Ocean employees have access to the PURE ATS or Subscriber Confidential Information. Third, once approved, the Ocean employee must complete Ocean's annual Compliance training.

Ocean employees who have access to Subscriber Confidential Information are subject to Ocean's "Information Barriers and Conflict Management Policies and Procedures". Pursuant to these procedures, Ocean employees are prohibited from sharing Subscriber Confidential Information with other employees (including at Nasdaq) who are not expressly authorized to receive such information. All Ocean employees are also subject to Nasdaq's Global Trading Policy ("GTP"), which outlines all requirements and restrictions related to personal trading activity, including holding periods, annual attestations, IPO restrictions, and a prohibited list. Ocean employees are required to disclose personal investment and brokerage accounts, positions, and transactions. Nasdaq's Global Ethics Team monitors personal trade activities against the GTP. Ocean also conducts electronic communications reviews to identify policy violations, including non-compliance with the above-referenced policies and procedures.

In addition to the foregoing, Ocean maintains written policies and procedures concerning unauthorized disclosures, which include escalation procedures for such incidents. In this regard, Ocean will promptly notify PURE of any actual or suspected unauthorized disclosure of confidential information, which includes Subscriber Confidential Information (so long as not prohibited by applicable laws, rules, or regulations).

PURE has the right to audit Ocean's operation of the ATS, including Ocean's access to and use of Subscriber Confidential Information, either through audits conducted by PURE's own audit team or by third-party auditors. Such audits may be conducted onsite or offsite.

In addition to Ocean personnel, Ocean has retained S3 to submit trade reports to the Consolidated Audit Trail ("CAT") on PURE's behalf.  Accordingly, certain S3 personnel have access to PURE Subscriber identifying information and order and trade information, which are components of Subscriber Confidential Information.  Only S3 personnel that are required to perform approved tasks (i.e., performing the trade reporting functions on PURE's behalf via its relationship with Ocean) are authorized to access the relevant Subscriber Confidential Information (as described above). To ensure that only authorized personnel access the relevant Subscriber Confidential Information, and that authorized personnel only use such access to perform approved functions, S3 performs periodic access audits. An attestation setting forth the results of these audits are provided to PURE. In addition to the results of these audits, S3 will notify PURE of any actual or suspected unauthorized disclosure of confidential information, which includes Subscriber Confidential Information.

PURE ATS ACCESS PROTECTIONS:

PURE possesses information that is sensitive and valuable, including the ATS's proprietary information and Subscriber Confidential Information. The exposure of sensitive information to unauthorized individuals could cause irreparable harm to the ATS and its Subscribers and could subject the ATS to fines or other regulatory sanctions. Additionally, if ATS information is tampered or interfered with, damaged, or made unavailable, it could impair the ATS's ability to do business. Therefore, the ATS requires its employees to diligently protect both the
ATS's proprietary information as well as the Subscriber Confidential Information of current and former Subscribers.

Access to Subscriber Confidential Information is limited to PURE employees with a legitimate business need for the information. Presently, for the reasons explained above, this includes all current PURE employees. Hard copy documents must be secured by locking the file cabinet or office in which they are stored and shredded when it is timely and appropriate to destroy them. Subscriber Confidential Information kept on the ATS's computers must be password-protected and secured behind firewalls.

PURE also has detailed written firm-wide policies and procedures designed to monitor employee personal trading. To address potential conflicts of interest, PURE's employee trading policy requires: (i) disclosure of all personal trading accounts for activity monitoring purposes; and (ii) employees to provide advance notice to PURE Compliance of all personal transactions. Further, PURE employees are prohibited from entering orders for personal transactions while the ATS is open for trading (i.e., 9:30am to 4:00pm on business days, absent an early close or holiday). Personal trading that has an appearance of impropriety (e.g., potential front-running) is prohibited. On an annual basis, PURE employees participate in Compliance training that addresses information protection and Subscriber confidentiality. Additionally, on a firm-wide basis, PURE continuously monitors electronic communications to identify potential policy violations.

**7b. Can a Subscriber consent to the disclosure of its confidential trading information?** —

**7d. Summary of roles of persons with access to confidential trading information:**
The below personnel teams or units have access to Subscriber Confidential Information. The basis for approved access to Subscriber Confidential Information is to service and/or support PURE ATS in different capacities. Access to Confidential Subscriber Information is generally through PUMA, which is used in connection with: (i) monitoring transactional activity; (ii) Subscriber and regulatory support; (iii) compliance and risk monitoring; (iv) intra-day and EOD Regulatory reporting; and (v) billing.  Only PURE employees have access to PUMA. In addition to PUMA, PURE's employee teams can also access Subscriber Confidential Information via Ocean's ATS monitoring application, OceanView, and Nasdaq SMARTS Trade Surveillance, (an automated compliance application that facilitates PURE's monitoring of all trading activity on the ATS for compliance with applicable laws, rules, regulations, and ATS policies by surveilling for potentially improper or disruptive trading activity).

1. PURE management, comprised of the CEO, COOs, CTO, and CCO.

2. ATS Subscriber Support. Provides support to Subscribers and/or their clients, including with respect to onboarding, use and implementation of the ATS protocols, and orders, transaction, and general inquiries.

3. Market and ATS Operations. Responsible for the day-to-day operation of the ATS.  This team monitors the ATS and related applications to ensure that they are operating as designed. This team is also involved with software development and changes to the ATS, ad hoc data analysis, and data archiving. This team also monitors for external market anomalies that could impact PURE ATS Subscribers and general system health. In addition to monitoring the system via PUMA, the Markets Operations team will have access to OceanView and Nasdaq SMARTS.

4. Internal Controls and Compliance. Responsible for risk, non-ATS technology, compliance, and operations.  While not all functional responsibilities in the internal team require access to Subscriber Confidential Information, given the likely overlap of roles and supervision, all members of the team will have access to Subscriber Confidential Information, including via PUMA, OceanView, and Nasdaq SMARTS.

5. Ancillary and Back-office Support. Includes support teams such as legal and finance and accounting.

Note that as stated in Part II, Item 6, above, PTT personnel are all associated persons with PURE.  These Shared Personnel generally function in a similar or equivalent capacity at PTT as they do at PURE (e.g., PURE management is PTT management; and PURE legal personnel perform legal responsibilities at PTT).  All Shared Personnel are subject to the written safeguards and written procedures to protect Subscriber Confidential Information described in this section, and are not permitted to use Subscriber Confidential Information that they have access to for unauthorized purposes.

All PURE employees will receive annual training on Subscriber Confidential Information.

With respect to service-providers, Ocean, S3 (via arrangement with Ocean), and Instinet, will have access to Subscriber Confidential Information.

In connection with the services Ocean is providing PURE, Ocean employees whose roles with respect to the ATS require access to such information, will have access to Subscriber Confidential Information, including orders, executions, and risk settings. These employees are from Ocean groups including Compliance, Operations, Technology Development (including trading and surrounding systems), Product Management, and Business Management.

In connection with its outsourcing arrangement with Ocean, S3 employees who require such access to perform trade reporting on behalf of the ATS, will have access to PURE Subscriber identifying information and order and trade information, which are components of Subscriber Confidential Information.

In connection with clearing services provided, Instinet receives all of the executions of PURE ATS's Subscribers. The details of such executions include the quantity, side, symbol, time, and price of the execution. As part of its relationship with PURE, Instinet is obligated to protect all Subscriber Confidential Information, including data and information related to Subscribers.  Further, Instinet is an SEC and FINRA-registered broker-dealer, and subject to applicable laws, rules, and regulations concerning information security standards and obligations.

### Part III: Manner of Operations

**1. Types of Subscribers:** Brokers, Dealers

**2a. Is a Subscriber required to be a registered broker-dealer?** Yes

**2b. Are there any other conditions for eligibility to become a Subscriber?** Yes

   - **Conditions:** PURE ATS allows as Subscribers those applicants who satisfy certain eligibility requirements. Specifically, Subscribers must meet the following requirements:

(1) Be a broker-dealer registered with the SEC and a member of at least one SRO.

(2) Pass Office of Foreign Asset Control ("OFAC") checks and pass disciplinary/regulatory reviews. The disciplinary/regulatory review will include reviewing public information to determine if the potential Subscriber has a disciplinary history that would preclude trading on the PURE ATS.

(3) Satisfy such technical or systems requirements as may be prescribed by PURE ATS, including, but not limited to: connectivity certification, the ability to send orders and cancellations, and to receive trades, cancellations, rejects, and trade breaks from the PURE ATS.

(4) Have clearing and settlement systems and/or arrangements in place to support participation on PURE ATS, as described further in Part III, Item 22.

(5) Execute PURE ATS's subscriber agreement ("Subscriber Agreement").

(6) Execute all other applicable agreements required to facilitate clearance, settlement, trade reporting, error correction, and cancellation of trades effected on or through the PURE ATS.

PURE ATS shall, after receiving a signed Subscriber Agreement and any additional documentation requested, in its discretion, approve or reject such applicant's request to become a Subscriber, or approve the subscription subject to such conditions and/or restrictions as it considers appropriate (e.g., potentially limiting the number of orders a Subscriber may send). PURE processes all agreements and completes its review and approval/denial process within thirty calendar days of reception of each signed Subscriber Agreement.

PURE ATS creates and maintains records of all such decisions granting access, denying access, and granting limited or restricted access, for each applicant, and the reasons for so doing.

**2c. Are the conditions for eligibility the same for all persons?** —

**2d. Is there a written agreement required to use the ATS?** Yes

**3a. Are there any conditions under which a Subscriber may be excluded?** Yes

   - **Conditions:** PURE, in its sole discretion, can exclude, in whole or in part, a Subscriber due to legal, credit, and/or order management behavior in PURE ATS. Potential reasons for exclusion include, but are not limited to:

1. Failure to make timely settlement of transactions and/or failure to settle trades.
2. Credit risk, as measured by publicly available proxies for credit risk (when available) and FINRA FOCUS reports.
3. The Subscriber's order management behavior on the ATS (e.g., order entry and cancellation) that is inconsistent with liquidity seeking (e.g., orders (firm or conditional) that are permitted to rest for long periods and canceled promptly (or fail to be firmed up) after a match reflect information seeking, and are not consistent with liquidity seeking).

**3b. Are these conditions the same for all Subscribers?** —

**4a. Hours of Operation:**
PURE ATS operates on business days from 8:00am to 5:00pm ET and follows the NASDAQ Exchange's holiday and early close schedule. The order book is open for firm and conditional orders beginning at 8:00am on business days.

PURE ATS conducts trading during both regular trading hours and outside of regular trading hours.

REGULAR TRADING HOURS:
PURE ATS conducts regular trading between 9:30am until 4:00pm ET on business days.  Because PURE ATS references the Official Closing Print for its final regular trading hours trade, PURE ATS's final regular trading hours trade occurs shortly after 4pm ET once the official closing trade is reported.

POST-CLOSE:
PURE ATS conducts trading outside of regular trading hours between the market close (4:00pm ET on regular trading days) ("Market Close") and the PURE ATS Close ("PSC").  PURE ATS refers to the period between the Market Close and the PSC as the Post-Close Trading Session.  PSC is a PURE ATS-specific mechanism.  PSC is at 4:30pm ET (or 30 minutes after the Market Close on days with an early close schedule).  Please see Part III, Item 18 (Trading Outside of Regular Trading Hours) for a description of PURE ATS trading behavior during the Post-Close Trading Session.

**4b. Are the hours of operation the same for all Subscribers?** Yes

**5a. Are Subscribers permitted to enter orders and other messages by electronic means?** Yes

   - **Protocols:** Subscribers enter all order flow, including both firm and conditional orders, directly into the ATS by way of a dedicated gateway into Ocean using the FIX 4.2 connection.

PURE does not provide market access, order routing, or algorithms.  To the extent that Subscribers provide direct market access to its clients ("DMA," as that term is defined in Exchange Act Rule 15c3-5(a)(1)(i)) to its institutional customers ("DMA Users")), such DMA Users may direct orders to PURE via the Subscriber (consistent with Regulation NMS Rule 600(b)(27), "directed orders" for purposes of this disclosure means that a Subscriber's customer is specifically instructing the Subscriber to route to a particular venue; DMA Users cannot enter order flow directly onto the ATS or via PURE).  All orders are routed to the ATS by the Subscriber and the DMA-providing Subscriber is the broker of record for all orders (and, as such, orders and related actions are attributable as Subscriber actions in this Form ATS-N).

All firm and conditional orders, regardless of how they are entered onto the ATS, or if they are entered with a particular order instruction, including the "Sub-Market Matching Instructions" (comprised of SDSP (Subscriber-Dedicated Sub-Pool), LMSP (Liquidity Maker Sub-Pool), or PRO (Pre-Routing Optimizer), (explained below in Part III, Item 14)), are entered through the FIX connection.

**5b. Are these protocols the same for all Subscribers?** —

**5c. Are there any other means to enter orders?** —

**5d. Are the terms and conditions for other means the same for all Subscribers?** —

**6a. Are co-location services offered?** No

**6c. Are any other means offered that reduce the latency of communications?** No

**6e. Are any other means offered that reduce the latency of communications between the ATS and its Subscribers?** No

**7a. Order Types and Attributes:**
PURE ATS is a crossing venue that matches compatible Subscriber orders and generatesfills for those matches based on referencing publicly available market data, including thevolume and associated price, of each SIP-reported trade as they occur, the Official Closing Price ("OCP"), and the NBBO.  The venue's matching, reference, and crossing logic is primarily governed by the use of PURE ATS order types ("Order Types").  Each Order Type seeks fills referencing adefined set of market data.  PURE ATS offers Subscribers the following order types:
Streaming Block orders; Liquidity Seeking orders; and Reference-on-Close orders (each,an "Order Type").  PURE ATS Order Types are described in detail in this Item under
"Order Types."

PURE ATS "matches" are bilateral pairings of compatible orders.  Compatible orders arematched in accordance with the logic described in the "Inter-Order Type Compatibility
Ranking" and "Matching" sections below (in this Item and in Part III, Item 11, Trading
Services, Facilities and Rules).  PURE ATS generates two types of matches:

(i)	A "single point match," which results in a single point-in-time fill attributed toeach order in the match, i.e., one single point match will result in one fill.  Or,

(ii)	A "streaming match," which results in a series of "child fills" (a "stream")attributed to each order in the match, i.e., one streaming match will result inmultiple fills.  On the PURE ATS, "child fill" means a trade executed by the ATSfor a streaming match and is meant to indicate that one streaming match willpotentially be associated with multiple fills.

A streaming match will continue uninterrupted so long as both orders in thematch have quantity and remain "marketable" (as such term is defined below inthis Item).

The type of match is determined by the Order Types that are matched, as described in this Item and in Part III, Item 11 (and Part III, Item 18 for the Post-Close Trading Session).  ATS rules may apply differently to single point matches and streaming matches; where applicable, such distinctions are noted in this Form ATS-N.

Upon matching, the ATS executes fills for each matched order.  The terms of all fills (both single point-in-time fills and streaming child fills), are governed by the Order Types, and execution logic described in this Item and in Part III, Item 11 (and Part III, Item 18 for the Post-Close Trading Session).

The remainder of this section provides additional detail on the (i) Order Types acceptedon the ATS; (ii) how orders are prioritized; (iii) marketability (bid/offer) requirements;
(iv) how Order Types can interact on the ATS; (v) ATS matching rules; (vi) minimumstream quantity, allocation and price discovery (execution logic); (vii) order modificationand cancellation; and (viii) Time-in-Force (TIF)/order instructions.  It also sets forthnumerous examples meant to illustrate these principles. Note that this section applies to both regular hours trading and the Post-Close Trading Session unless otherwise noted in this Form ATS-N.

Order Types

Each firm and conditional order sent to the ATS will include a symbol, size, price, marketside, a liquidity transfer rate (explained below), and a Time-in-Force, among other terms.

(1)	Streaming Block

Streaming Block orders are exclusively seeking a streaming match that references SIP-reported trades using a matched liquidity transfer rate ("LTR") during regular trading hours (in the Post-Close Trading Session, this Order Type is seeking a single point match with an ROC order that references the OCP (see Part III, Item 18)).

PURE ATS has four Streaming Block orders that Subscribers can use.  Each Streaming Block has anassociated minimum LTR and a maximum LTR that indicates the LTR range that the
Subscriber will accept.  A streaming match will have a matched LTR that satisfies bothmatched orders (see Matching section in this Item and Part III, Item 11).  The matched
LTR is a rate percentage that PURE ATS uses to determine the size of child fills in astreaming match.  More specifically, the size of the child fills in the streaming match isthe matched LTR percentage multiplied against the quantity of each SIP-reported trade
(SIP-reported trades are referred to as reference trades throughout this Form ATS-N)subject to the order's residual quantity (no order will receive a fill larger than its residual quantity) and the ATS's minimum stream quantity conditions ("MSQ") in accordance withthe execution logic described in this item (see the MSQ example below in this item).  Theprice of each child fill is the weighted average price of the reference trades that contributeto achieving the MSQ (see the MSQ example below in this item).  Additional descriptionof the PURE ATS compatibility, matching, and execution logic is described below in this
Item under "Inter-Order Type Compatibility Ranking," "Matching" and "Minimum
Stream Quantity, Allocation, and Price Discovery".

Upon a child fill being effected (i.e., a trade being effected), the quantity of the child fillis then decremented against the total quantity of the matched order (decrementing isfurther explained and illustrated in "Inter-Order Type Compatibility and Matching" foundbelow in this Item).  The matched LTR can then be continuously applied to eachsuccessive SIP-reported trade to create a series of child fills in a stream.  The stream cancontinue over time, without any time limitations (during the course of an entire tradingday with any remaining quantities cancelled at the end of a trading day).

 Streaming Block orders can be firm or conditional.

The Streaming Block orders are:

1.	10-200% ("200%")

This Streaming Block is seeking a child fill quantity of 200% of the quantity of eachcontemporaneous SIP-reported trade but will accept at least 10%.  This means thatfor a SIP-reported trade of 100 shares, the 200% Streaming Block will accept 200shares to 10 shares for that child fill at the price of the SIP-reported trade.

2.	5-30% ("30%")

This Streaming Block is seeking a child fill quantity of 30% of the quantity of eachcontemporaneous SIP-reported trade but will accept at least 5%.  This means that fora SIP-reported trade of 100 shares, the 30% Streaming Block is seeking 30 shares to
5 shares for that child fill at the price of the SIP-reported trade.

3.	5-15% ("15%")

This Streaming Block is seeking a child fill quantity of 15% of the quantity of eachcontemporaneous SIP-reported trade but will accept at least 5%.  This means that fora SIP-reported trade of 100 shares, the 15% Streaming Block is seeking 15 shares to
5 shares for that child fill at the price of the SIP-reported trade.

4.	Custom LTR Range ("Custom")

This Streaming Block is seeking a child fill quantity based on the Custom parametersentered.  Custom orders require both a minimum and maximum LTR, and must bewithin the range of .1-500%; the minimum and maximum LTR of a Custom ordermay be equal.  For example, a Custom order with a 2% minimum and a 4%maximum, will accept 2 shares to 4 shares in a child fill referencing a SIP-reportedtrade of 100 shares, at the price of the SIP-reported trade.

Note that the examples above are illustrative.  For the avoidance of doubt, PURE ATSwill only generate child fills in accordance with the MSQ conditions described below.

(2)	Liquidity Seeking ("LS")

During regular trading hours, this Order Type is seeking a single point match that references the NBBO.  If such match is not available, LS orders will also accept a streaming match at the highest available LTR (compatibility, matching, and execution logic is described below in this Item under "Inter-Order Type Compatibility Ranking," "Matching" and "Minimum Stream Quantity, Allocation, and Price Discovery").

In the Post-Close Trading Session, this Order Type is seeking a single point match with an ROC order that references the OCP (see Part III, Item 18).

Subscribers can set a maximum LTR up to 3,000% for LS orders, which is the default LTR maximum for such order types. The LTR maximum will be considered for any streams that the LS order enters (LTR is not considered for single point matches). Subscribers can set a minimum LTR for LS orders; otherwise, the default minimum LTR for an LS order is 5%. These orders can be firm or conditional.

(3)	Reference-on-close ("ROC")

This Order Type is seeking only a single point match that references the OCP for up to its full quantity during the Post-Close Trading Session (compatibility and matching and execution logic is described below in this Item under "Inter-Order Type Compatibility Ranking," "Matching" and "Minimum Stream Quantity, Allocation, and Price Discovery" and in Part III, Item 18).  This Order Type will not match prior to the OCP being disseminated, will not trade using any reference other than the OCP, and will not enter a streaming match.  ROC orders do not have an LTR range but rather have an unlimited LTR.  The unlimited LTR for ROC orders cannot be changed. ROC orders must be firm orders.

Intra-Order Type Prioritization

PURE ATS uses intra-order prioritization logic to rank orders within the same Order
Type (note that for these purposes, Streaming Block is considered one Order Type).  Thissection should be read in conjunction with the Inter-Order Type Compatibility Rankingsection below in this Item, and in Part III, Item 11, for purposes of ranking for matches.

Within each Order Type, firm and conditional orders are prioritized based on (i) LTR, (ii)size of the order, (iii) marketability (as defined below), and (iv) time the order wasreceived, in that sequence.  The ATS processes (i.e., assesses for matching compatibility,as described below) firm orders prior to conditional orders regardless of the order termsof the conditional orders.

The first term considered in intra-Order Type prioritization ranking is the LTR.  Ordersare prioritized by the highest maximum LTR.  (The ROC Order Typealways has an unlimited maximum LTR and therefore when prioritizing such ordersamong like Order Types, PURE ATS will always need to look at least to the size of therelevant orders).

The following example demonstrates the intra-Order Type prioritization if the ATSreceived the three orders chronologically:

Buy Order 1: 15% Streaming Block
Buy Order 2: 200% Streaming Block
Buy Order 3: 25% (Custom) Streaming Block

Regardless of any other terms of the orders (e.g., size, marketability, or time), the intra-
Order Type prioritization would be based on maximum LTR, as follows:

Buy Order 2 (Highest maximum LTR)
Buy Order 3 (2nd highest maximum LTR)
Buy Order 1 (3rd highest maximum LTR)

For two orders with the same LTR, the second term considered in intra-Order Typeprioritization ranking is the size of the order quantity. The larger the order, the higher thestanding.  For example, if the ATS received the following three orders chronologically:

Buy Order 1: 15% Streaming Block, for 25,000 shares
Buy Order 2: 15% Streaming Block, for 5,000 shares
Buy Order 3: 15% Streaming Block, for 50,000 shares

The prioritization would be:
Buy Order 3 (50,000 shares)
Buy Order 1 (25,000 shares)
Buy Order 2 (5,000 shares)

The third term considered in intra-Order Type prioritization ranking (i.e., for orders thatare the same LTR and of equal size) is the marketability of the order.  The marketabilitystandard depends on the (i) relevant match type and (ii) reference point.

The marketability of an order for a potential streaming match is the difference betweenthe order's limit price and the contra-side NBBO.  For instance, if the NBBO is $10.01 x
$10.02 and the limit of a buy order is $10.05, the marketability of an order is .03.  Thegreater the marketability, the higher the standing in terms of priority.

To illustrate prioritization for a potential stream match, if the ATS received the followingthree orders chronologically:

Buy Order 1: 15% Streaming Block, for 25,000 shares, marketable by 4 cents
Buy Order 2: 15% Streaming Block, for 25,000 shares, marketable by 10 cents
Buy Order 3: 15% Streaming Block, for 25,000 shares, marketable by 6 cents

The prioritization would be:
Buy Order 2 (10 cents marketable)
Buy Order 3 (6 cents marketable)
Buy Order 1 (4 cents marketable)

An order is marketable for a single point match referencing the NBBO (this applies to LSorders only) if the order's limit price at least satisfies its peg instruction (peg instructionsare described in Item 11c).  The more aggressive the limit price, the higher the standingin terms of priority.  Single point-in-time trades are described below in the "Minimum
Stream Quantity, Allocation, and Price Discovery" section and Examples 9 and 10 of thisresponse.

An order is marketable for a single point match referencing the OCP (this applies to Streaming Block, LS, and ROC orders) if the order's limit price is at least through the OCP.  The more aggressive the limit price, the higher the standing in terms of priority.

The final term considered in intra-Order Type prioritization ranking (i.e., for orders thatare the same LTR, equal size, and have equal marketability) is the time the order arrived,with priority being assigned chronologically.  Note that time priority for ROC orders takes into account the time orders arrive on the ATS during regular hours trading and the Post-Close Trading Session, i.e., ROC orders arriving at 10 am, 3 pm, and 4:02 pm, would be prioritized in that order (all else being equal).   Given the aforementioned prioritization logic, it is by system design that orders arriving later could feasibly be given higher priority than earlier arriving orders.

Minimum Marketability Threshold

For an order to be eligible for a streaming match, it must be marketable by a minimumthreshold (the "minimum marketability threshold") (minimum marketability thresholdsare not applied to single point matches).  The minimum marketability thresholds are seton a stock-by-stock basis and are neither publicly available nor made available to
Subscribers and can be set at any integer, including zero.  PURE ATS can modify theminimum marketability threshold for particular stocks to account for volatility, includingin the event of anomalous volatility of the overall market, relevant sector, or a specificstock.  To monitor for circumstances that may warrant modifying the minimummarketability threshold, PURE considers various volatility proxies such as the VIX,
Implied Volatilities, and Realized Volatilities of single stocks, sector indices, and/ormarket-wide indices.  The minimum marketability thresholds are manually updated by
PURE Market Operations and are reviewed biannually.

For example, for a stock with a minimum marketability threshold of 2 cents that isexperiencing significantly higher price volatility, the minimum marketability thresholdcould be increased to 4 cents.  This would require a buy order to have a limit of 4 centshigher than the current national best offer, and a sell order to have a limit of 4 centsbelow the current national best bid to be eligible for a streaming match.

PURE believes that modifications to the minimum marketability threshold in thesecircumstances promotes matches that yield more efficient streams between Subscribers.

Note that minimum marketability thresholds are only relevant to the creation of astreaming match (i.e., to be eligible for a match, an order must meet the minimummarketability threshold).  Once an order is in a streaming match, so long as the orderremains marketable (i.e., the order's limit price is priced at or through its respective
NBBO farside), the order will remain in the match.  If a matched order ceases to bemarketable, the streaming match will end.

For example, if the NBBO is $10.01 x $10.02, for a stock with a minimum marketabilitythreshold of 4 cents, a sell order would need to be priced at $9.97 to be eligible for astreaming match.  Once matched, the order would only need to remain marketable toremain in the streaming match.  If the order became unmarketable, i.e., the NBBO movedto $9.96 X $9.97, the streaming match would end.  To become eligible for a streamingmatch again (with the previous matched order or any other order), the sell order wouldagain need to meet minimum marketability thresholds at the then-prevailing NBBO.

Inter-Order Type Compatibility Ranking

PURE ATS will only match orders of Order Types that are compatible.

(1)	Streaming Block Orders:  Streaming Block orders are compatible to match with LS and
Streaming Block orders during the regular trading hours, prioritized by Order Type in that order.

During the Post-Close Trading Session, upon the dissemination of the OCP, firm and conditional Streaming Block orders are exclusively compatible with ROC orders in accordance with the parameters described in Part III, Item 18.  For the avoidance of doubt, because ROC orders are not eligible for matches during regular trading hours, the presence of ROC orders on the ATS order book during regular trading hours does not inhibit matches of LS and Streaming Block orders.

(2)	LS Orders:  The LS Order Type is compatible to match with the LS and Streaming Block orders during regular trading hours prioritized by Order Type in that order.

During the Post-Close Trading Session, upon dissemination of the OCP, firm and conditional LS orders are exclusively compatible with ROC orders in accordance with the parameters described in Part III, Item 18.  For the avoidance of doubt, because ROC orders are not eligible for matches during regular trading hours, the presence of ROC orders on the ATS order book during regular trading hours does not inhibit matches of LS and Streaming Block orders.

(3)	ROC Orders:  The ROC Order Type is not compatible with any Order Type until the OCP has been disseminated.  Until that point, ROC orders are not eligible for any match and will remain resting on the ATS order book.  Upon the dissemination of the OCP, the ROC Order Type is compatible to match with ROC orders, LS orders, and Streaming Block orders, prioritized by Order Type in that order.

Matching

Matches are bilateral (i.e., between only two orders).  For a match to occur, two ordersmust be compatible.

Compatibility means that among compatible Order Types (described above) there is (i) abuy and sell order in the same security, (ii) both meeting the minimum marketabilitythreshold (not applicable to single point matches), (iii) with overlapping LTRs (i.e., the
LTR minimum to maximum range of one order overlaps with the LTR minimum tomaximum range of another order), and (iv) that any additional order handling instructionssent with the orders (as described below in Part III, Item 11, Additional Order
Parameters) are satisfied.

In searching for a match for an order, the ATS first considers inter-Order compatibilityranking.  If there are multiple compatible contra-side orders with equal inter-Ordercompatibility ranking, the ATS will look to the intra-Order Type prioritization ranking ofthe relevant orders.

The following examples illustrate the application of the PURE ATS inter-Order Typecompatibility logic (example assumes orders are compatible on all terms not reflected):

Example 1 - Incoming LS Order
Orders 1-3 are resting on the ATS during regular trading hours (all orders are firm).
Order 1 is a buy order for 5,000 shares in the LS Order Type.
Order 2 is a buy order for 5,000 shares in the 15% Streaming Block (min. of 5%, max. of
15%).
Order 3 is a buy order for 5,000 shares in the ROC Order Type.

Order 4 arrives in the PURE ATS and is a sell order for 5,000 shares in the LS Order
Type.

The compatible orders for Order 4 would be prioritized as:
Order 1
Order 2
Order 3 would not be ranked during regular trading hours.

Example 2 - Resting ROC orders
Orders 1-4 are resting on the ATS when the OCP is disseminated (allorders are firm).
Order 1 is a buy order for 5,000 shares in the LS Order Type.
Order 2 is a buy order for 5,000 shares in the 15% Streaming Block Order Type (min. of
5%, max. of 15%).
Order 3 is a buy order for 5,000 shares in the ROC Order Type.
Order 4 is a sell order for 5,000 shares in the ROC Order Type.

The compatible orders for Order 4 would be prioritized as:
Order 3
Order 1
Order 2

Example 3 - Incoming Streaming Block order
Orders 1 and 2 are resting on the ATS during regular trading hours (all orders are firm).
Order 1 is a buy order for 5,000 shares in the LS Order Type.
Order 2 is a buy order for 5,000 shares in the 15% Streaming Block (min. of 5%, max. of
15%).

Order 3 arrives in the PURE ATS and is a sell order for 5,000 shares in the 200%
Streaming Block.

The compatible orders for Order 3 would be prioritized as:
Order 1
Order 2

Matches will result in the following: (i) streaming matches are created at the highestpossible LTR satisfying both matched orders (the highest LTR within the acceptablerange for each matched order); and (ii) single point matches are created at the highestpossible quantity that satisfies both matched orders (see also Part III, Item 18, for match behavior during the Post-Close Trading Session).

If an order has residual quantity or LTR after being matched, the order's decrementedquantity or LTR will be available for other matches, meaning the order can be in multiplematches concurrently.  Note that for prioritization purposes, a decremented ordermaintains its original priority standing on the order book (e.g., an order using the 200%
Order Type with a residual 170% LTR following a match, is still treated as a 200% Order
Type for purposes of prioritization).

The following examples illustrate the interaction of Streaming Block orders with different LTRS:

Example 4 - Compatible LTRs:
Order 1 is a buy order for 5,000 shares in the 15% Streaming Block Order Type (min. of
5%, max. of 15%).
Order 2 is a sell order for 5,000 shares in the 15% Streaming Block Order Type (min. of
5%, max. of 15%).

These orders have overlapping LTRs because the LTR ranges of the orders overlap.
Thus, the orders are eligible to be matched.  The orders will be matched at 15%, which isthe highest common LTR between the two orders (in this example, this also happens tobe the maximum LTR for each order).

Example 5 - Incompatible LTRs:
Order 1 is a buy order for 5,000 shares in the 15% Streaming Block Order Type (min. of
5%, max. of 15%).
Order 2 is a sell order for 5,000 shares in the Custom Streaming Block Order Type, witha 1% minimum and a 4% maximum LTR.

These orders do not have overlapping LTRs because Order 2's LTR range (1% to 4%)does not overlap with Order 1's LTR range (5% to 15%).  Thus, these orders are noteligible to be matched.

Example 6 - Compatible But Different LTRs:
Order 1 is a buy order for 5,000 shares in the 30% Streaming Block Order Type (min. of
5%, max. of 30%).
Order 2 is a sell order for 5,000 shares in the 15% Streaming Block Order Type (min. of
5%, max. of 15%).

These orders have overlapping LTRs because the LTR ranges of the orders overlap.
Thus, the orders are eligible to be matched.  The orders will be matched at 15%, which isthe highest common LTR between the two orders.  Order 1 will also have a residual LTRof 15%, which will rest in the ATS order book awaiting other potential matches.

Example 7 - Compatible LTRs and Concurrent Matching:
Order 1 is a buy order for 10,000 shares in the 15% Streaming Block Order Type (min. of
5%, max. of 15%).
Order 2 is a buy order for 10,000 shares in the 15% Streaming Block Order Type(min. of
5%, max. of 15%).
Order 3 is a sell order for 20,000 shares in the 30% Streaming Block Order Type (min. of
5%, max. of 30%).

Here, Order 3 has overlapping LTRs with both Order 1 and Order 2, and has sufficient
LTR to match with both contra-side orders.  Therefore, Order 3 will enter two concurrentmatches, one with Order 1 and a second with Order 2.  In this way, Order 1 and Order 2will satisfy their maximum LTR of 15%, and Order 3 will achieve its maximum LTR of
30% (two matches each at 15% LTR).

Example 8 - Compatible LTRs and Sequential Matching:
Order 1 is a buy order for 10,000 shares in the 30% Streaming Block Order Type (min. of
5%, max. of 30%).
Order 2 is a buy order for 10,000 shares in the 30% Streaming Block Order Type (min. of
5%, max. of 30%).
Order 3 is a sell order for 20,000 shares in the 30% Streaming Block Order Type (min. of
5%, max. of 30%).

Here, Order 3 has overlapping LTRs with both Order 1 and Order 2, but only has LTR tomatch with one of the orders since the orders will be matched at the highest common
LTR -- here 30%.  Since Order 1 is prioritized over Order 2, Order 3 and Order 1 form amatch at a 30% LTR.  Order 2 will remain resting on the ATS order book.  However,because Order 3 is larger in size than Order 1, Order 3 will have a residual 10,000 sharesto sell once Order 1's buy order is completed.  Therefore, once Order 1's quantity is fullyexhausted, Order 3 will form a match with Order 2, which will continue as a stream untilboth Order 3 and Order 2 are fully exhausted (since Order 3's residual 10,000 shares tosell is equal to Order 2's 10,000 shares to buy).

Please see ATS-N Part III ITM.7a for the remainder of this response.

**7b. Are the order types, attributes, and instructions the same for all Subscribers?** —

**8a. Does the ATS require a minimum or maximum order size?** —

**8c. Are odd-lot orders accepted and executed?** —

**8d. Are odd-lot procedures the same for all Subscribers?** —

**8e. Are mixed-lot orders accepted and executed?** Yes

   - **Procedures:** Mixed lots are treated the same as round lots as long as they meet the minimum order size.

**8f. Are mixed-lot procedures the same for all Subscribers?** Yes

**9a. Does the ATS send any messages to indicate trading interest?** —

**10a. Opening/Re-opening/Closing Procedures:**
PURE ATS accepts firm and conditional orders beginning at 8:00am ET and matching in the order book for firm and conditional orders occurs during regular market hours (9:30am to 4:00pm ET) and during the Post-Close Trading Session per Part III, Item 18.  With respect to opening, the firm and conditional orders will remain in an accepted state and no executions will occur until the matching engine detects the following execution triggers:(i) the first trade from the primary listing exchange for the relevant symbol, (ii) an NBBO, and (iii) the opening time. Note that the first trade from the primary listing exchange may be the opening auction trade or a trade that occurs before the opening auction (given each exchange's opening processes). The matching engine will reference either of these types of trades, so long as the other two execution triggers are detected. Once the matching engine begins trading, the standard priority logic and matching logic will be applied respectively to any open firm or conditional orders.

Following a stoppage of trading in a security during regular trading hours, PURE ATS will not execute transactions until the matching engine detects the first trade from the primary listing exchange for the relevant symbol, an NBBO, and the re-opening time (for an exchange-initiated stoppage) or pricing information (for a PURE ATS-initiated stoppage). In addition to the aforementioned criteria, a LULD band from the primary exchange is required for a single point-in-time trade between two LS contra orders (firm or conditional) to occur for both the start of trading or re-opening of trading. If the primary listing exchange does not reopen (or pricing information is unavailable) after a stoppage the PURE ATS will not match firm or conditional orders in the security.

**10b. Are these procedures the same for all Subscribers?** Yes

**10c. Unexecuted Orders Procedures:**
When the ATS begins matching orders, any resting firm or conditional orders will be subject to the prioritization and marketability rules described in Part III, Item 7.

In the event of a PURE ATS trading halt (as described in Part III, Item 20, PURE ATS may implement a trading halt in response to internal issues impacting the ATS, including for technological issues), all orders will be cancelled back to Subscribers.

**10d. Is there any difference in execution procedures during trading hours?** Yes

**10e. Is there any difference in pre-opening or execution procedures following a stoppage?** No

**11a. Structure of the NMS Stock ATS:**
PURE ATS is a crossing venue that matches compatible Subscriber orders and generatesfills for those matches based on referencing publicly available market data, including thevolume and associated price, of each SIP-reported trade as they occur, the OCP, and the NBBO.
The venue's matching, reference, and crossing logic is primarily governed by the use of
PURE ATS Order Types.

PURE ATS "matches" are bilateral pairings of compatible orders.  Compatible orders arematched in accordance with the logic described in the "Inter-Order Type Compatibility
Ranking" and "Matching" sections below (in this Item and in Part III, Item 7).

Upon matching, the ATS executes fills for each matched order.  The terms of all fills
(both single point-in-time fills and streaming child fills), are governed by the Order
Types, and execution logic described in this Item and in Part III, Item 7.

The ATS is available for trading in NMS stocks only.

**11b. Are the means that facilitate access the same for all Subscribers?** —

**11c. Rules and procedures of the NMS Stock ATS:**
The ATS order book matches compatible firm or conditional orders with marketable pricelimits at the highest compatible quantity or LTR.  Upon matching, the ATS executes fillsfor each matched order using the relevant market data reference point(s) in accordancewith the logic described in this Item and in Part III, Item 7 (and for the Post-Close Trading Session, as described in Part III, Item 18).

Intra-Order Type Prioritization

PURE ATS uses intra-order prioritization logic to rank orders within the same Order
Type (note that for these purposes, Streaming Block is considered one Order Type).  Thissection should be read in conjunction with the Inter-Order Type Compatibility Rankingsection below in this Item, and in Part III, Item 7, for purposes of ranking for matches.

Within each Order Type, firm and conditional orders are prioritized based on (i) LTR, (ii)size of the order, (iii) marketability (as defined below), and (iv) time the order wasreceived, in that sequence.  The ATS processes (i.e., assesses for matching compatibility,as described below) firm orders prior to conditional orders regardless of the order termsof the conditional orders.

The first term considered in intra-Order Type prioritization ranking is the LTR.  Ordersare prioritized by the highest maximum LTR.  (The ROC Order Type always has an unlimited maximum LTR and therefore when prioritizing such orders among like Order Types, PURE ATS will always need to look at least to the size of the relevant orders).

For two orders with the same LTR, the second term considered in intra-Order Typeprioritization ranking is the size of the order quantity. The larger the order, the higher thestanding.

The third term considered in intra-Order Type prioritization ranking (i.e., for orders thatare the same Order Type and of equal size) is the marketability of the order.  Themarketability standard depends on the (i) relevant match type and (ii) reference point (see
Part III, Item 7).

The final term considered in intra-Order Type prioritization ranking (i.e., for orders thatare the same LTR, equal size, and have equal marketability) is the time the order arrived,with priority being assigned chronologically.  Given the aforementioned prioritizationlogic, it is by system design that orders arriving later could feasibly be given higherpriority than earlier arriving orders.

Inter-Order Type Compatibility Ranking

PURE ATS will only match orders of Order Types that are compatible.  See Part III, Item
7 "Inter-Order Type Compatibility Ranking" section for complete list of Order Typecompatibility rankings.

Matching

Matches are bilateral (i.e., between only two orders).  For a match to occur, two ordersmust be compatible.

Compatibility means that among compatible Order Types (described above) there is (i) abuy and sell order in the same security, (ii) both meeting the minimum marketabilitythreshold (not applicable to single point matches), (iii) with overlapping LTRs (i.e., the
LTR minimum to maximum range of one order overlaps with the LTR minimum tomaximum range of another order), and (iv) that any additional order handling instructionssent with the orders (as described below in this Item 11, Additional Order Parameters) aresatisfied.

In searching for a match for an order, the ATS first considers inter-Order compatibilityranking.  If there are multiple compatible contra-side orders with equal inter-Ordercompatibility ranking, the ATS will look to the intra-Order Type prioritization ranking ofthe relevant orders.

Matches will result in the following: (i) streaming matches are created at the highestpossible LTR satisfying both matched orders (the highest LTR within the acceptablerange for each matched order); and (ii) single point matches are created at the highestpossible quantity that satisfies both matched orders. See Part III, Item 18, for match behavior during the Post-Close Trading Session.

If an order has residual quantity or LTR after being matched, the order's decrementedquantity or LTR will be available for other matches, meaning the order can be in multiplematches concurrently.  Note that for prioritization purposes, a decremented ordermaintains its original priority standing on the order book (e.g., an order using the 200%
Order Type with a residual 170% LTR following a match, is still treated as a 200% Order
Type for purposes of prioritization).

Minimum Stream Quantity, Allocation, and Price Discovery

Single point-in-time trade execution logic:

During regular trading hours, when two orders eligible for a single point match are matched (e.g., LS-LS,), they will execute a single point-in-time trade for the largest quantity possible (i.e., the smaller quantity of the two orders matched).  Note that given the minimum order size requirements for orders on PURE ATS, minimum stream quantity is not applicable to single point-in-time trades.

The price of the single point-in-time trade will be set in accordance with the referencedmarket data as dictated by the matched Order Types (e.g., NBBO), the limit price, and peg instructions, if applicable, for the two relevant orders (executions will not violate an order's limit price).  Peg instructions (see Part III, Item 11c under "Peg Order Instructions for LS Orders") are applicable only to LS orders and are used (with limit prices) to determine compatibility for an LS-LS match and the price of any resulting single point-in-time trade. For single point-in-time trade execution logic in the Post-Close Trading Session, see Part III, Item 18.

Streaming matches (during regular trading hours; there are no streams in the Post-Close Trading Session):

Once a streaming match has occurred, the ATS will use each observed SIP-reported tradein the relevant security as reference trades to execute "child fills" in accordance with
PURE ATS execution (see under "Order Types") and MSQ logic.

Note that each SIP-reported trade is only referenced once in each stream (and allconcurrent streams in the ATS reference each SIP-reported trade once).  The ATSreferences SIP-reported trades in real-time as they are reported in succession (subject tothe filtering logic described in Part III, Item 23, below).  (To the extent that there aremalfunctions or other issues with the SIP that result in time gaps, the procedures set forthin Part III, Item 20, below will be applied).  In the event that there is no SIP-reportedtrade after the match is formed, the orders will remain matched but there will be no childfills, and therefore no stream (i.e., a match can exist without a stream).

All streaming child fills are governed by the MSQ logic (for in detailed description of
MSQ logic see Part III, Item 7a, "Minimum Stream Quantity, Allocation, and Price
Discovery").

A stream will continue uninterrupted providing "child fills" as long as both orders remainmarketable (i.e., the orders' limit prices are priced at or through the contra-side NBBO),have quantity remaining, and have not been cancelled.

Below is an example applying the ATS's streaming matching logic to a series of orders:

Example 16:
The ATS receives three Buy orders in the following chronology:
Buy Order 1: 15%
Buy Order 2: 30%
Buy Order 3: 200%

The prioritization of the orders will be:
Buy Order 3 (Highest maximum LTR)
Buy Order 2 (2nd highest maximum LTR)
Buy Order 1 (3rd highest maximum LTR)

For a marketable incoming sell order (Sell Order 4), using the 200% Streaming Block
Order Type:
Stream 1 would be created at an LTR of 200% between Buy Order 3 and Sell Order 4.
Buy Order 2 and Buy Order 1 would continue to rest because Sell Order 4's 200% ratewas completed.

For a marketable incoming sell order (Sell Order 5), also using the 200% Streaming Block
Order Type:
Stream 2 would be created at an LTR of 30% between Buy Order 2 and Sell Order 5.
Sell Order 5's available LTR is decremented to 170%.
And
Stream 3 would be created at an LTR of 15% between Buy Order 1 and Sell Order 5.
Sell Order 5's available LTR is decremented to 155%.

After the creation of Stream 2 & 3, only Sell Order 5 will be resting in the order book witha remaining LTR of 155%.  Sell Order 5 is participating in two streams, Stream 2 &
Stream 3.

The LTR of each stream:
Stream 1 (Order 3&4) LTR: 200%
Stream 2 (Order 2&5) LTR: 30%
Stream 3 (Order 1&5) LTR: 15%

Given the following three contemporaneously processed trade reports from theconsolidated tape:
SIP-reported Trade 1: 1,000 @ $36.99
SIP-reported Trade 2: 50 @ $36.9925
SIP-reported Trade 3: 200 @ $37

And given an MSQ for the relevant symbol is set at 5 shares:

The orders in Stream 1 (comprised of Order 3 and Order 4) will receive the followingchild fills:
Stream 1 Child Fill 1: 2,000 @ 36.99
Stream 1 Child Fill 2: 100 @ 36.9925
Stream 1 Child Fill 3: 400 @ 37

The orders in Stream 2 (comprised of Order 2 and Order 5) will receive the followingchild fills:
Stream 2 Child Fill 1: 300 @ 36.99
Stream 2 Child Fill 2: 15 @ 36.9925
Stream 2 Child Fill 3: 60 @ 37

The orders in Stream 3 (comprised of Order 1 and Order 5) will receive the followingchild fills:
Stream 3 Child Fill 1: 150 @ 36.99
Stream 3 Child Fill 2: 8 @ 36.9925
Stream 3 Child Fill 3: 30 @ 37

The aggregated traded volumes in this example are as follows:
SIP Volume: 1,250 shares
PURE ATS Volume: 3,063
		Stream 1: 2,500 shares
			Order 3: 2,500 shares
			Order 4: 2,500 shares
		Stream 2: 375 shares
			Order 2: 375 shares
			Order 5: 375 shares
		Stream 3: 188 shares
			Order 1: 188 shares
			Order 5: 188 shares

Please note that Order 5 participated in two streams, and in aggregate sold 563 shares (375shares in Stream 2 and 188 shares in Stream 3).

Maximum Executable Quantity

PURE ATS references the OCP for its final regular trading hours trade for matched orders.  The maximum fill shares an order can receive referencing the OCP (aggregated between the regular trading hours and the Post-Close Trading Session), is governed by its Maximum Executable Quantity ("MaxEQ").  The MaxEQ for Streaming Block orders equals the lesser of the order's (i) residual quantity or (ii) maximum-sought LTR times the OCP volume.  For example, a 1,000-share Streaming Block order seeking an LTR up to 30% in a symbol with an OCP of 5,000 shares at $10.00 will have a MaxEQ of 1,000 shares (the lesser of 1,000 and 1,500).  The MaxEQ for LS and ROC orders equals an order's residual quantity (ROC orders will only reference the OCP in the Post-Close Trading Session).  An order's MaxEQ can be satisfied via multiple fills referencing the OCP that are decremented against the order's MaxEQ (multiple fills are described in Part III, Item 18).

Additional Order Parameters

The standard prioritization logic will be impacted when a Subscriber elects to use "Sub-Market Matching Instructions" (comprised of SDSP (Subscriber-Dedicated Sub-Pool), LMSP (Liquidity Maker Sub-Pool), or PRO (Pre-Routing Optimizer)) or imposes a self-match customization constraint or conditional order restriction (implemented via a FIX message from the Subscriber; these order instructions are explained in Part III, Item 14.a). These parameters each limit potential counter-parties or contra-side orders for a respective order; otherwise, the standard prioritization logic applies to the impacted orders.

Further, Subscribers can route orders (via FIX) with minimum execution quantities
("MEQ") for (i) ROC orders and (ii) for LS orders where the Subscriber sets the minimum
LTR to be greater than the highest available LTR for all other available Order Types onthe ATS.  The effect of setting the minimum LTR at this level is to limit potentialcompatible contra-side orders to only LS orders.  Where a Subscriber sets an MEQ for anorder, the order will only be matched in the ATS to a contra-side order that can satisfy the
MEQ (and is otherwise compatible with the order).

PURE ATS does not support post-only or counter-party segmentation or classification.

Peg Order Instructions for LS Orders:

PURE ATS requires peg instructions for all LS orders.  PURE ATS recognizes three peginstructions: (i) Peg Far; (ii) Peg Mid; and (iii) Peg Near (defined below).  PURE ATSwill assign a Peg Mid instruction to (i) any LS order routed to the ATS without adesignated Peg instruction; and (ii) any LS order with a minimum LTR less than or equalto 500%.

Peg instructions are effected only in the case of two LS orders (i.e., a Peg instruction willnot be considered for stream matches or for LS-ROC matches referencing the OCP).  PURE ATS uses the LS order's peg instruction and its limit price to determine the order's compatibility and the price for a potential single point-in-time trade.  The peg order instruction defines where an order is executable inrelation to the then-prevailing NBBO; the limit price defines where an order is executablewith respect to a set price point.  PURE ATS will not execute a single point-in-time tradeat a price that violates an order's peg instruction, and will never execute a trade thatviolates an order's limit price.

For clarity, for LS orders:

*	Peg Far means that an order will be executed to (and including) the then-prevailing contra-side NBBO (but not in violation of the order's limit price).

*	Peg Mid means that an order will be executed to (and including) the then-prevailing NBBO midpoint (but not in violation of the order's limit price).

*	Peg Near means that an order will be executed to (and including) the then-prevailing near-side NBBO (but not in violation of the order's limit price).

Note that as a result of this logic, an order with a marketable limit price and priority butthe most restrictive peg instruction (e.g., Peg Near) will not be eligible for a match wherethe only contra-side interest has a Peg Mid or Peg Near instruction.

For illustrative purposes:

In a stock with an NBBO of $10.00-$10.10, a Buy LS order with a $10.20 limit price and:

*	Peg Far instruction is eligible for a single point-in-time trade up to $10.10;
*	Peg Mid instruction is eligible for a single point-in-time trade up to $10.05;
*	Per Near instruction is eligible for a single point-in-time trade up to $10.00.

In a stock with an NBBO of $10.00-$10.10, a Buy LS order with a $10.07 limit price and:

*	Peg Far instruction is eligible for a single point-in-time trade up to $10.07;
*	Peg Mid instruction is eligible for a single point-in-time trade up to $10.05;
*	Per Near instruction is eligible for a single point-in-time trade up to $10.00.

In a stock with an NBBO of $10.00-$10.10, a Buy LS order with a $9.99 limit price andany Peg Instruction is not eligible for any trade because it is not marketable (the limitprice is below the near-side NBBO).

Minimum Match Quantity ("MMQ"): Order instruction (sent to the ATS via FIX field) for Streaming Block orders only. The instruction allows Subscribers to set a minimum order quantity for a contra-side order that it will accept in a match; if a contra-side does not meet the minimum order quantity, it will not be compatible with the Subscriber's order. Subscribers may set the MMQ between 100 and 1,000 for all Streaming Block orders; the default MMQ for all incoming Streaming Block orders is 1,000 shares. MMQ is applied only to Streaming Block orders that are not in a current stream (i.e., MMQ is not applied to matches resulting in incremental, concurrent streams for a particular order, as described in Part III, Item 7 and illustrated in Example 7). There is no MMQ for non-Streaming Block orders.

Price Limits, Marketability, Protection, and Improvement:
No orders will receive an execution that would violate the order's limit price.  In order tooptimize the creation of streams, the order book uses minimum marketability thresholdsrequired prior to an order being eligible to match (as described in Part III, Item 7).

There is no price improvement from, nor will the price vary from the price of the tradesreferenced by the ATS.

Short Sales and Regulation SHO:
The ATS's Subscribers are limited to U.S. registered broker-dealers that are obligated tocomply with Regulation SHO Rule 203(b)(1).

When Regulation SHO Rule 201 short sale restrictions are in effect for a particular NMSstock, PURE will cancel (previously accepted) and reject (incoming) firm and conditionalshort sale orders in the relevant stock, except for short sale LS orders with a minimum
LTR greater than or equal to 501% ("Constrained LS Orders") that are permissibly pricedfor execution.  The ATS will continue to execute such Constrained LS Orders pursuant tothe policies and procedures adopted pursuant to Rule 201(b) of Regulation SHO.

Locked and Crossed Markets:
PURE ATS will not execute single point-in-time trades when the market is crossed. PURE
ATS will only execute single point-in-time trades when the market is locked if both thebuyer and seller specify on the order that they are willing to execute during a lockedmarket.  During a (i) locked market or (ii) crossed market the PURE ATS will reference SIP-reported trades as described in Part III, Item 23a.

Time Stamping of Orders and Executions:
Firm and conditional orders are timestamped at the time they are accepted by the systemin microseconds.  The formation of a stream and each trade fill is also timestamped inmicroseconds.  The ATS will timestamp Subscriber firm and conditional orders incompliance with FINRA time stamp and clock synchronization rules and guidance.

Errors:
PURE has Written Supervisory Procedures regarding errors, and errors will be handledconsistent with the firm's error policies.  For ATS (not Subscriber) errors, PURE maintains an error account at its Clearing Broker (Instinet) to book bona fide errors, and to trade out of them.  Key elements of the ATS error policy include the following:

1) Errors must be escalated to the CCO immediately;
2) Errors must be corrected and documented as soon as practicable;
3) The ATS cannot be used to liquidate an error; and
4) PURE will not cover losses for Subscribers by treating transactions as errors whenthey are not.

**11d. Are these rules and procedures the same for all Subscribers?** Yes

**12a. Are there any arrangements to provide liquidity?** —

**13a. Is order or trading interest segmented?** —

**13b. Is the segmentation the same for all Subscribers?** —

**13c. Does segmentation depend on whether the order is from a customer?** No

**13d. Are segmentation categories disclosed to Subscribers?** —

**13e. Is the disclosure the same for all Subscribers?** —

**14a. Is a Subscriber designated to interact with specific trading interest?** Yes

   - **Details:** Orders can be designated to interact or not interact with certain other orders or trading interest using specific order instructions.  These instructions include: (1) SDSP (Subscriber-Dedicated Sub-Pool); (2) LMSP (Liquidity Maker Sub-Pool); (3) PRO (Pre-Routing Optimizer) (SDSP, LMSP, and PRO, comprising the Sub-Market Matching Instructions); (4) self-match customization; and (5) conditional order interaction instructions.

An order designated with a Sub-Market Matching Instruction is eligible to match only with either a discrete subset or restricted set of orders, per the terms of the specific instruction.  With respect to these instructions: (i) Subscribers must elect to use these instructions for the subject orders (in coordination with their DMA Users, if applicable); (ii) these instructions only impose counter-party limitations for the designated subject order itself; and (iii) the designated subject order can only interact with other orders that are eligible for such interaction (e.g., if a Subscriber does not make an order eligible to interact with orders in an LMSP, it will not).

(1) With SDSP (formerly HMMP), Subscribers can request a dedicated Sub-Pool that enables a Subscriber to use the streaming protocol while limiting its counter-parties to firm and conditional orders sent by the same Subscriber (which may include directed orders from DMA clients) to the designated Sub-Pool. There is no integration between any SDSP and the ATS central order book or other Sub-Pool, i.e., orders designated to a particular SDSP will only interact with other orders in the same Sub-Pool and will not interact with orders in the ATS's central order book or orders in any other Sub-Pool.  To the extent an order routed to an SDSP does not have a compatible match in the SDSP, the order will remain resting in the SDSP (subject to, for example, Subscriber cancellation).  Participants in an SDSP are free to send orders to the ATS's central order book, but to do so, they must send separate orders to each destination. Use of an SDSP is a Subscriber decision and, other than limiting the universe of eligible counter-parties and contra-side orders, the orders (and any match) remain subject to the same ATS priority and matching logic described in Part III, Item 7.

(2) The LMSP modifier, only available where a Subscriber sponsors the Sub-Market Matching Instruction (and provides DMA, where applicable), allows Subscribers to designate orders as maker liquidity subject to maker-taker pricing (as discussed in Part III, Item 19, maker-taker pricing is applicable only to orders with the LMSP modifier).  Subscribers may also choose to permit their DMA Users to direct orders designated with the LMSP modifier to the ATS via the Subscriber (who is at all times the broker of record).  This modifier is available to all Subscribers and can be used for firm and conditional orders.

LMSP order flow must be routed through an LM ID, a unique identifier designated for such use.  An LM ID will be attributed to a single Subscriber-designated LM order flow(s) (e.g., a particular trading desk, strategy, or DMA User(s)). PURE will provide any Subscriber with LM IDs upon request.  In the event that a DMA User requests an LM ID directly from PURE, PURE will provide a unique LM ID to the Subscriber sponsoring the Sub-Market Matching Instruction, subject to the approval of the relevant Subscriber (DMA Users are not Subscribers, have no direct connection to the ATS, and are not able to enter orders directly onto the ATS or to PURE).  The DMA-providing broker is the PURE Subscriber and the broker of record on all firm and conditional orders and "firm-up" orders received, and the entity that will receive any maker rebates from PURE (which are negotiated with the relevant Subscriber).

Each LM ID will be associated with a single LM order flow in a discrete "LM Sub-Pool," i.e., each LM Sub-Pool will have LM order flow from a single LM ID.  All Subscribers may seek liquidity in (i.e., interact with) any LM Sub-Pool via LS IDs (or enable a DMA User to do so).  All requests with respect to LM IDs, LS IDs, and LM Sub-Pools may be delivered verbally or in writing to PURE.  PURE will inform ATS participants or potential participants (e.g., broker-dealers considering becoming ATS Subscribers) considering accessing the ATS of the number of LM Sub-Pools operating, if any.

Once an LM Sub-Pool is configured (i.e., an LM ID is assigned), participating liquidity seekers and makers can (but are not required to) designate orders to be routed to the LM Sub-Pool.

There is no integration between any Sub-Pool and the ATS central order book for Sub-Pool liquidity seekers or makers.  Orders designated to a particular LM Sub-Pool will only interact with other orders in the same LM Sub-Pool and will not interact with orders in the ATS's central order book or orders in any other LM Sub-Pool.  Participants in an LM Sub-Pool are free to send orders to the ATS's central order book or other LM Sub-Pools, but to do so, they must send separate orders to each destination.

Within an LM Sub-Pool, all orders are subject to the matching and trading protocols as in the ATS's central order book.  This includes that any order from a liquidity seeker or maker can interact with any other compatible order regardless of the counterparty.  For the avoidance of doubt, there is no prioritization or matching benefit to LM order flow.

(3) The PRO order instruction is a functionality provided by the ATS to its Subscribers. The functionality enables a Subscriber to permit its customer to send directed orders (firm and conditional) to the ATS in which the directed order's potential counter-parties are limited to that Subscriber's inventory on the ATS (i.e., the directed order will only match with an order sent to the ATS through the same Subscriber). All orders with the PRO order instruction are automatically designated as IOC (in the case of an LS Order Type) or SOK. Use of a PRO order instruction is both a customer and Subscriber decision and, other than limiting the universe of eligible counter-parties, the orders (and any match) remain subject to the same ATS priority and matching logic described in Part III, Item 7.

(4) PURE ATS also offers Subscribers self-match customization that allows a Subscriber to either prevent executions with other firm or conditional orders from that Subscriber in the ATS or restrict executions to only firm or conditional orders from that Subscriber in the ATS. Self-match customization allows a subscriber to have flexible customized matching functionality in the ATS and can be applied to orders ATS pool-wide (except that this customization is not available for orders designated to LM Sub-Pools). Subscribers can apply this customization at different levels of granularity (e.g., at the Subscriber or Subscriber's customer level; the latter would prevent orders from a Subscriber's customer from interacting with other orders in the ATS from that customer).

(5) In addition to limiting counter-parties, Subscribers can also choose to restrict (or not restrict) any order from interacting with contra-side conditional orders. Note that if a Subscriber enables an order with an IOC or SOK time-in-force instruction to interact with conditional orders, to facilitate such an interaction, if the ATS identifies a potential match for the IOC or SOK order with a conditional order, the ATS will delay cancelling the IOC or SOK order pending the firm-up request process for the relevant conditional period (the firm-up request process has a two-second time-out period, and is described in Part III, Item 9).

PURE ATS does not segment flow; only Subscribers and their customers can limit order interactions using the order instructions described in this section.

All of the above order instructions can be sent by the Subscriber (including for directed orders) via its FIX connection with PURE ATS in accordance with PURE ATS's FIX specifications (available to all Subscribers).

**14b. Is the counter-party selection the same for all Subscribers?** —

**15a. Does the ATS use electronic communications to display order and trading interest?** No

**15b. Is order and trading interest displayed to anyone other than Subscribers?** Yes

   - **Details:** PURE ATS does not display firm or conditional orders. As part of the firm-up process described in Part III, Item 9, PURE ATS makes conditional orders known to Subscribers with the potential contra-side matching order via FIX. The only relevant conditional order information made known to each Subscriber during the firm-up process is the quantity of the contra-side trading interest and LTR that would be subject to the potential match (i.e., a Subscriber will not be made aware if the contra-side order has additional quantity, the contra-side Order Type, price, etc.).

**15c. Are the display procedures the same for all Subscribers?** —

**16a. Are orders or other messages routed out of the ATS?** No

**17a. Is there any difference between the treatment of order and trading interest based on source?** No

**17b. Is the treatment the same for all Subscribers?** Yes

**18a. Does the ATS execute trades outside of its regular trading hours?** —

**19a. Fees:**
The PURE ATS uses two fee structures: a per share model and a subscription model.

Under the per-share model, fees are charged on a per share basis and can range from $0.0005 to $0.0025. The per-share fee structures are separately negotiated with each individual Subscriber and all terms may vary.  In negotiating fee structures, PURE primarily considers a combination of: (i) historical trading volume and patterns; (ii) anticipated trading volume and patterns; (iii) competitive considerations (e.g., venue-wide subscriber, market participation, market access, and product terms); and (iv) the method(s) by which orders arrive on the ATS, including whether the order access method is systematic (e.g., access methods (i) and (ii), below) or manually directed (e.g., access methods (i) and (iii), below) (lower fees are generally considered for systematic order flow, though that may vary by Subscriber and specific order flow).  Orders may arrive on the ATS:

(i)	As directed by a Subscriber (systematically or manually);
(ii)	As directed by a DMA User systematically (e.g., algorithmically) via a Subscriber;
(iii)	As directed by DMA User manually (e.g., EMS) via a Subscriber;
(iv)	With the SDSP instruction (described more fully in Part III, Item 14);
(v)	With the LMSP modifier (described more fully in Part III, Item 14); or
(vi)	With the PRO instruction (described more fully in Part III, Item 14).

PURE ATS also offers agreements under a subscription model.  The subscription model is available to all Subscribers that provide for systematic (i.e., algorithmic) directed order flow from DMA Users (meaning that the Subscriber's customer is instructing the Subscriber to send the relevant orders to PURE ATS through the Subscriber's market access connections ((i)(a) above); however, PureStream may limit the number of agreements available under the subscription model at a given time.  Under the subscription model, Subscribers are charged a flat fee in connection with directed DMA User orders.  The flat fee and relevant terms are negotiated with Subscribers on a case-by-case basis primarily in consideration of (i) historical trading volume and patterns; (ii) anticipated trading volume and patterns; and (iii) competitive considerations (e.g., venue-wide subscriber, market participation, market access, and product terms).  The range of flat fees per share when applied to expected volume per each subscription agreement is $0.0005 to $0.0025.

These fee models are not mutually exclusive and a Subscriber may route orders to PURE ATS subject to both structures.  The terms of each fee model and the applicability to a specific Subscriber's order flow will be set forth in each Subscriber's agreement with PureStream.

As described in FINRA Rule 6897 (Consolidated Audit Trail Funding Fees), Executing Brokers (as that term is defined for purposes of that rule) are assessed CAT regulatory fees. As used in the FINRA rule, PURE is identified as the CAT Executing Broker for the buyer in each transaction on PURE ATS and is therefore assessed CAT regulatory fees in that capacity; the Subscriber-seller is identified as the Executing Broker for the seller and is separately assessed CAT regulatory fees. PURE does not pass on CAT regulatory fees that it is assessed as the Executing Broker for the buyer.

**19b. Bundled Services/Fees:**
PURE does not provide any non-ATS products or services.

**19c. Rebates and Discounts:**
LM Sub-Pools have maker-taker rebate pricing.  Rebates are issued to the Subscriber of record on an LM ID when the ATS executes a trade in an LM Sub-Pool that involves an order routed through an LM ID (only available for LM order flow).  Only the Subscriber of record for the LM ID receives a rebate.

Rebates are not issued in connection with orders that are not routed through an LM ID (these orders are subject to negotiated fees as described in Part III, Item 19(a)), and the chronological entry time between two matched orders is not relevant to rebates.

Rebates are on a per-share traded basis and rebate structures may range from $0.0005 to $0.0025, and are negotiated individually for LM IDs with Subscribers.  In negotiating rebate rates, PURE will consider anticipated liquidity posting volume, anticipated trading volume, and ongoing volumes once the LM Pool is active.

**20a. Suspension of Trading Procedures:**
PURE's Market Operations team will monitor the ATS's performance throughout each trading day to ensure that the system is functioning properly. Note that PURE also has a back-up (i.e., secondary) version of the PURE ATS matching system in the event that the primary system experiences a malfunction. The back-up version is located at the same physical address as that of the primary system.

The Market Operations team will also ensure that the matching engine is suspended in the event of  external (to the ATS) issues including a regulatory halt, Regulation SHO Rule 201 state, or situation regarding SIP market data inaccuracies or disruptions. In the event of a suspension for these reasons, the ATS will continue to accept new orders (firm and conditional) and open orders will remain on the order book (subject to Subscriber modification and cancellation), but PURE ATS will not execute orders, in the applicable symbols.

PURE ATS can also suspend system functionalities for internal issues impacting the ATS. In these scenarios, PURE ATS may pause or halt the system. During a pause, the ATS will continue to accept new orders (firm and conditional) and open orders will remain on the order book (subject to Subscriber modification and cancellation) but the ATS will not execute orders in the applicable symbols. During a halt, the ATS will cancel open orders, reject new orders, and no orders will be executed, in the applicable symbols. The determination to pause or halt depends on the applicable facts and circumstances at issue but as a general matter pauses are implemented for security-specific issues (e.g., a clearing issue specific to a symbol), whereas halts are implemented for broader technological issues.

PURE can effect the stoppage of trading per symbol and/or Subscriber. In order to suspend all trading in the ATS, PURE must instruct Ocean and cannot effect the change itself.

PURE and Ocean will also monitor for fair access thresholds on a symbol-level basis. There are three (3) different validations to measure the approach of any given symbol towards 5% of total market volume.

The first check is called "Early Validation". On the last three (3) days of the month, a query will be run to determine if a symbol has traded more than 4.5% of total market volume in three (3) of the prior five (5) months, including the current month. If so, the symbol is halted for trading on the platform for the remainder of the month.

The second check is called "3 out of 5". On the first day of the next month, a query will be run to determine if a symbol has traded more than 4.5% of total market volume in three (3) of the prior five (5) months, excluding the current month. If so, the symbol is halted for trading on the platform for the remainder of the month.

The third and final check is called "4 out of 6". On each day of every month, a query is run to determine if a symbol has traded more than 4.5% of total market volume in four (4) of the prior five (5) months, including the current month. If so, the symbol is halted for trading on the platform for the remainder of the month and PURE is alerted of the breach. This breach should never occur since the "3 out of 5" check will block a symbol from trading four (4) months at above 4.5% of total market volume.

**20b. Are these procedures the same for all Subscribers?** Yes

**21a. Trade Reporting Arrangements:**
PURE uses the NASDAQ TRF as its primary trade reporting facility. Ocean will initiate and manage the submission of reports, which PURE will confirm. The NASDAQ TRF2 is the back-up trade reporting facility for the ATS. If the primary TRF is not available, Ocean will failover to the back-up TRF on behalf of the PURE ATS where any unreported trades will be resubmitted.

All reportable transactions effected on PURE ATS are over-the-counter transactions that are trade-reportable pursuant to applicable trade reporting requirements.  Reportable transactions on the PURE ATS include all child fills and single point-in-time trades as those terms are used herein.  For the avoidance of doubt, Derived Shares are used for internal counting (see Part III, Item 7a), and are not reportable transactions.

**21b. Are these arrangements the same for all Subscribers?** Yes

**22a. Clearance and Settlement Arrangements:**
PURE has engaged Instinet to clear and settle all transactions executed on behalf of the ATS. Instinet receives all ATS transactions over FIX and submits the transactions executed on the ATS to the NSCC for clearance and settlement. Each Subscriber must acknowledge and consent to this arrangement and provide their own clearing information for the purpose of clearing and settlement. For operational reporting purposes, Instinet submits executed transactions to the NSCC that designate PURE as the counter-party to all trades.

**22b. Are these arrangements the same for all Subscribers?** —

**23a. Market Data Sources:**
PURE ATS consumes SIP market data via feed handler software from Ocean to determine the OCP, NBBO, and protected quotes, as well as to price, prioritize, execute, and remove firm and conditional orders and trading interest on the ATS. Trades on the SIPs are comprised of exchange-reported and TRF-reported trades. PURE ATS also uses the SIP data to provide support services to Subscribers.

For the PURE ATS, SIP-reported trades means (i) continuous market trades that update the last sale, and (ii) odd lots. PURE ATS will not consider other trades that do not update the last sale (e.g., sold sales and derivatively priced trades).SIP-reported trades originating on exchanges are referenced as-is. SIP-reported trades originating on the TRF are only referenced if they have not traded through the relevant NBBO range during the corresponding 1-second window. To ensure that the order did not trade through the relevant NBBO range, the ATS uses FINRA TRF Timestamp 1 (defined as the participant's time stamp) and cross references the system's corresponding NBBO window at the participant's time stamp. PURE uses this approach because clock synchronization between the participant's timestamp and the NBBO window at that timestamp is more accurate than comparing the SIP-reported trade timestamp to the NBBO window at the time of the SIP timestamp.

**23b. Are these sources the same for all Subscribers?** Yes

**24a. Does the ATS aggregate Subscriber order and trading interest with that of other trading centers?** No

**25a. Did the ATS exceed the volume thresholds of Regulation ATS?** No

**26. Are order flow and execution statistics published?** —