FORM 8.3

PUBLIC OPENING POSITION DISCLOSURE/DEALING DISCLOSURE BY

A PERSON WITH INTERESTS IN RELEVANT SECURITIES REPRESENTING 1% OR MORE

Rule 8.3 of the Takeover Code (the “Code”)

1.         KEY INFORMATION

(a) Identity of the person whose positions/dealings are being disclosed: Magnetar Capital Partners LP
(b) Owner or controller of interests and short positions disclosed, if different from 1(a):
     The naming of nominee or vehicle companies is insufficient		 N/A
(c) Name of offeror/offeree in relation to whose relevant securities this form relates:
     Use a separate form for each offeror/offeree		CME Group Inc.
(d) If an exempt fund manager connected with an offeror/offeree, state this and specify identity of offeror/offeree: N/A
(e) Date position held/dealing undertaken: June 19, 2018
(f)  Has the discloser previously disclosed, or are they today disclosing, under the Code in respect of any other party to this offer? Yes – NEX Group plc

2.         POSITIONS OF THE PERSON MAKING THE DISCLOSURE

(a)        Interests and short positions in the relevant securities of the offeror or offeree to which the disclosure relates following the dealing (if any)

Class of relevant security: USD 0.01 Class A common stock
ISIN: US12572Q1058
InterestsShort positions
Number%Number%
(1) Relevant securities owned and/or controlled:165,876.05%
(2) Derivatives (other than options):23,171.01%
(3) Options and agreements to purchase/sell:

     TOTAL:		189,047.06%

All interests and all short positions should be disclosed.

Details of any open derivative or option positions, or agreements to purchase or sell relevant securities, should be given on a Supplemental Form 8 (Open Positions).

(b)        Rights to subscribe for new securities (including directors’ and other executive options)

Class of relevant security in relation to which subscription right exists:
Details, including nature of the rights concerned and relevant percentages:

If there are positions or rights to subscribe to disclose in more than one class of relevant securities of the offeror or offeree named in 1(c), copy table 2(a) or (b) (as appropriate) for each additional class of relevant security.

3.         DEALINGS (IF ANY) BY THE PERSON MAKING THE DISCLOSURE

(a)        Purchases and sales

Class of relevant securityPurchase/saleNumber of securitiesPrice per unit
Ordinary shares Sale 36 166.96
Ordinary shares Sale 50 167.008
Ordinary shares Sale 46 167.105
Ordinary shares Sale 8 167.025
Ordinary shares Short Sale 53 167.8002
Ordinary shares Short Sale 55 168.1373
Ordinary shares Short Sale 56 167.9243
Ordinary shares Short Sale 62 168.4398
Ordinary shares Short Sale 64 167.6388
Ordinary shares Short Sale 7 167.4921
Ordinary shares Short Sale 19 167.4779
Ordinary shares Short Sale 20 167.116
Ordinary shares Short Sale 21 166.9967
Ordinary shares Short Sale 5 167.792
Ordinary shares Purchase 6 167.3517
Ordinary shares Purchase 16 167.2306
Ordinary shares Purchase 16 167.5638
Ordinary shares Purchase 17 167.1953
Ordinary shares Purchase 20 167.114
Ordinary shares Purchase 38 167.2453
Ordinary shares Purchase 45 166.648
Ordinary shares Purchase 46 166.8763
Ordinary shares Purchase 48 167.1908
Ordinary shares Purchase 52 167.2315
Ordinary shares Purchase 62 167.3294
Ordinary shares Purchase 65 166.684
Ordinary shares Purchase 134 166.81
Ordinary shares Purchase 142 166.9421
Ordinary shares Purchase 199 166.8389

(b)        Derivatives transactions (other than options)

Class of relevant securityProduct description
e.g. CFD		Nature of dealing
e.g. opening/closing a long/short position, increasing/reducing a long/short position		Number of reference securitiesPrice per unit

 (c)       Options transactions in respect of existing securities

(i)         Writing, selling, purchasing or varying

Class of relevant securityProduct description e.g. call optionWriting, purchasing, selling, varying etc.Number of securities to which option relatesExercise price per unitType
e.g. American, European etc.		Expiry dateOption money paid/ received per unit

(ii)        Exercising

Class of relevant securityProduct description
e.g. call option		Number of securitiesExercise price per unit

(d)        Other dealings (including subscribing for new securities)

Class of relevant securityNature of dealing
e.g. subscription, conversion		DetailsPrice per unit (if applicable)

The currency of all prices and other monetary amounts should be stated.

Where there have been dealings in more than one class of relevant securities of the offeror or offeree named in 1(c), copy table 3(a), (b), (c) or (d) (as appropriate) for each additional class of relevant security dealt in.

4.         OTHER INFORMATION

(a)        Indemnity and other dealing arrangements

Details of any indemnity or option arrangement, or any agreement or understanding, formal or informal, relating to relevant securities which may be an inducement to deal or refrain from dealing entered into by the person making the disclosure and any party to the offer or any person acting in concert with a party to the offer:
If there are no such agreements, arrangements or understandings, state “none”

None

(b)        Agreements, arrangements or understandings relating to options or derivatives

Details of any agreement, arrangement or understanding, formal or informal, between the person making the disclosure and any other person relating to:
(i)  the voting rights of any relevant securities under any option; or
(ii) the voting rights or future acquisition or disposal of any relevant securities to which any derivative is referenced:
If there are no such agreements, arrangements or understandings, state “none”
None

(c)        Attachments

Is a Supplemental Form 8 (Open Positions) attached? No

   

Date of disclosure:June 20, 2018
Contact name:Audrey Newsom
Telephone number:847-905-4693

Public disclosures under Rule 8 of the Code must be made to a Regulatory Information Service and must also be emailed to the Takeover Panel atmonitoring@disclosure.org.uk.  The Panel’s Market Surveillance Unit is available for consultation in relation to the Code’s dealing disclosure requirements on +44 (0)20 7638 0129.

The Code can be viewed on the Panel’s website atwww.thetakeoverpanel.org.uk.