---
title: "SIX Exfeed SCAH Product Guide SIX Swiss Exchange; introduces hourly HHI concentration per day"
sdDatePublished: "2026-04-27T16:05:00Z"
source: "https://www.six-group.com/dam/download/market-data/exfeed/analytics/six-concentration-analytics-hourly-product-guide.pdf"
topics:
  - name: "financial service"
    identifier: "medtop:20001370"
locations:
  - "Switzerland"
  - "Zürich"
---


SIX Exfeed SCAH Product Guide SIX Swiss Exchange; introduces hourly HHI concentration per day

SIX

© SIX 04.2026
SIX-SCAH-GDE-110/E
Version 1.10, 01.04.2026
C1 Public

SIX Exfeed
SIX Concentration Analytics Hourly (SCAH) Product Guide

SIX Exfeed
SIX Concentration Analytics Hourly (SCAH) Product Guide
SIX-SCAH-GDE-110/E
Version 1.10, 01.04.2026

C1 Public
Page 2

Table of Contents
1
Introduction ................................................................................................................................................................ 3
1.1
Purpose and Scope ............................................................................................................................................................... 3
2
Data Format ................................................................................................................................................................ 3
2.1
File Format ............................................................................................................................................................................. 3
2.2
File Name ............................................................................................................................................................................... 3
3
Data Content ............................................................................................................................................................... 3
3.1
Security Universe .................................................................................................................................................................. 3
3.2
Execution Venues Covered .................................................................................................................................................. 3
3.3
Herfindahl-Hirschman Index (HHI)..................................................................................................................................... 4
3.4
Market Participant Identification ........................................................................................................................................ 4
3.5
Flow Classification ................................................................................................................................................................ 4
3.6
Data Fields ............................................................................................................................................................................. 5

SIX Exfeed
SIX Concentration Analytics Hourly (SCAH) Product Guide
SIX-SCAH-GDE-110/E
Version 1.10, 01.04.2026

C1 Public
Page 3

1
Introduction
1.1
Purpose and Scope
This Product Guide provides relevant information on SIX Concentration Analytics Hourly (SCAH) according to the
General Terms and Conditions for SIX Analytics Services.
This Product Guide does not take precedent over the Agreement on SIX Analytics Services (including the General
Terms and Conditions for SIX Analytics Services).
2
Data Format
2.1
File Format
SCAH is provided in a delimited text file (CSV) that uses a semicolon (“;”) to separate values.
2.2
File Name
The CSV file containing data for trading day YYYY-MM-DD has the file name
“six_hhi_granularity_hourly_YYYYMMDD.csv”. “granularity” is a placeholder for one of the two granularity levels as
defined in Section 3.4 and can take the values “memberorg” or “member”. For example, the data for April 19, 2023 for
granularity level “memberorg” is provided in the file called “six_hhi_memberorg_hourly_20230419.csv”.
3
Data Content
SCAH provides insights into market concentration on SIX Swiss Exchange per day and security.
3.1
Security Universe
SCAH is computed for securities in the following trading segments subject to the corresponding inclusion
requirements:
Trading Segment Name
Trading segment ID
Inclusion requirements
Blue Chip Shares
26 (until and including 4 December 2020)
and 25 (from 7 December 2020)
-
At least 20 trades
Mid-/Small-Cap Shares
591
-
At least 20 trades
Table 1
Security universe
The inclusion requirements are evaluated for each day, separately.
3.2
Execution Venues Covered
SCAH is computed for executions on the following order books:
Trading Segment Name
Order books
Blue Chip Shares
CLOB
Mid-/Small-Cap Shares
CLOB
Table 2
Execution venues covered

SIX Exfeed
SIX Concentration Analytics Hourly (SCAH) Product Guide
SIX-SCAH-GDE-110/E
Version 1.10, 01.04.2026

C1 Public
Page 4

3.3
Herfindahl-Hirschman Index (HHI)
Market concentration is measured by the Herfindahl-Hirschman Index (HHI). The HHI is the sum of the squared
market shares of all market participants.
It is calculated as follows:
𝐻𝐻𝐻𝐻𝐻𝐻= ෍𝑠𝑠𝑖𝑖
2
𝑁𝑁
𝑖𝑖=1

𝑠𝑠𝑖𝑖 denotes market share of market participant 𝑖𝑖, where,
𝑠𝑠𝑖𝑖=
𝑞𝑞𝑖𝑖
෌
𝑞𝑞𝑗𝑗
𝑁𝑁
𝑗𝑗=1

𝑞𝑞𝑖𝑖 represents the number of shares traded by market participant 𝑖𝑖, 𝑞𝑞𝑗𝑗 the number of shares traded by any market
participant, and 𝑁𝑁 denotes the total number of market participants.
Thus, the HHI can assume values from 0 to 1. In order to protect anonymity in markets with very high concentration,
no exact HHIs are provided for values above 0.6. Instead, 0.6 is specified.
3.4
Market Participant Identification
Market participants are identified on two levels of granularity, for each of which a separate CSV with separate HHI
calculations is provided on a daily basis:
Granularity Level
Comment
Member Organisation ID
Lower granularity level
Note: Sponsored users are considered separate member
organisations even though they route their orders via the
member organisation ID of the sponsoring participant.
Member ID
Higher granularity level
A member organisation may have several member IDs through
which orders are routed.
Table 3
Granularity levels of market participant identification
3.5
Flow Classification
Order flow is classified as follows:
Classification
Definition
Overall flow
All shares traded during continuous trading, auctions and
Trading-At-Last
Aggressive flow
Shares aggressively traded during continuous trading
Passive flow
Shares passively traded during continuous trading
Auction flow
Shares traded during auctions and Trading-At-Last
Customer flow
Trading under the risk-less principal capacity during
continuous trading, auctions and Trading-At-Last and not
originating from a Sponsored Access User
Non-customer flow
Shares traded under the principal capacity or originating from
a Sponsored Access User during continuous trading, auctions
and Trading-At-Last
Table 4
Market participant classification

SIX Exfeed
SIX Concentration Analytics Hourly (SCAH) Product Guide
SIX-SCAH-GDE-110/E
Version 1.10, 01.04.2026

C1 Public
Page 5

3.6
Data Fields
Field name
Format
Definition
date
str
Date in YYYY-MM-DD format
isin
str
ISIN code
currency
str
Trading currency
group
str
ID for symbol grouping (board only)
trading_segment_id
str
ID for trading segment
time_bucket
time
09:00-10:00
10:00-11:00
11:00-12:00
12:00-13:00
13:00-14:00
14:00-15:00
15:00-16:00
16:00-17:00
17:00-18:00
Time intervals are left-closed and right-open, i.e. [x,y).
The full hour at time y is assigned to the next interval.
hhi
float64
Market concentration of overall flow
hhi_buy
float64
Market concentration of overall buy flow
hhi_sell
float64
Market concentration of overall sell flow
hhi_aggressive
float64
Market concentration of aggressive flow
hhi_aggressive_buy
float64
Market concentration of aggressive buy flow
hhi_aggressive_sell
float64
Market concentration of aggressive sell flow
hhi_passive
float64
Market concentration of passive flow
hhi_passive_buy
float64
Market concentration of passive buy flow
hhi_passive_sell
float64
Market concentration of passive sell flow
hhi_auction
float64
Market concentration of auction flow
hhi_auction_buy
float64
Market concentration of auction buy flow
hhi_auction_sell
float64
Market concentration of auction sell flow
hhi_customer
float64
Market concentration of customer flow
hhi_customer_buy
float64
Market concentration of customer buy flow
hhi_customer_sell
float64
Market concentration of customer sell flow
hhi_noncustomer
float64
Market concentration of non-customer flow
hhi_noncustomer_buy
float64
Market concentration of non-customer buy flow
hhi_noncustomer_sell
float64
Market concentration of non-customer sell flow
trade_volume
int
Total buy and sell number of shares traded
aggressive_trade_volume
int
Total buy and sell number of shares aggressively traded during
continuous trading

SIX Exfeed
SIX Concentration Analytics Hourly (SCAH) Product Guide
SIX-SCAH-GDE-110/E
Version 1.10, 01.04.2026

C1 Public
Page 6

Field name
Format
Definition
passive_trade_volume
int
Total buy and sell number of shares passively traded during
continuous trading
auction_trade_volume
int
Total buy and sell number of shares traded during the auctions
and Trading-At-Last
customer_trade_volume
int
Total buy and sell number of shares traded under the risk-less
principal capacity and not originating from a Sponsored Access
User
noncustomer_trade_volume
int
Total buy and sell number of shares traded under the principal
capacity or originating from a Sponsored Access User
Table 5
Data fields

SIX Exfeed Ltd
Hardturmstrasse 201
8005 Zurich
Switzerland
T +41 58 399 2977
© SIX 04.2026