Holding(s) in Company

1. Identity of the issuer or the underlying issuerof existing shares to which voting rights areattached: ii

Mereo BioPharma Group PLC

2 Reason for the notification (please tick the appropriate box or boxes):

An acquisition or disposal of voting rights

No

An acquisition or disposal of qualifying financial instruments which may result in the acquisition of shares already issued to which voting rights are attached

No

An acquisition or disposal of instruments with similar economic effect to qualifying financial instruments

No

An event changing the breakdown of voting rights

No

Other (please specify):

Conversion of loan note and issue of equity

Yes

3. Full name of person(s) subject to thenotification obligation: iii

Invesco Ltd.

4. Full name of shareholder(s) (if different from 3.):iv

5. Date of the transaction and date onwhich the threshold is crossed orreached: v

26 April 2017

6. Date on which issuer notified:

28 April 2017

7. Threshold(s) that is/are crossed orreached: vi, vii

27%

8. Notified details:

A: Voting rights attached to shares viii, ix

Class/type ofshares

if possible usingthe ISIN CODE

Situation previousto the triggeringtransaction

Resulting situation after the triggering transaction

NumberofShares

NumberofVotingRights

Numberof shares

Number of votingrights

% of voting rights x

Direct

Direct xi

Indirect xii

Direct

Indirect

Ordinary Gbp 0.003 Shares

GB00BZ4G2K23

19,932,931

19,932,931

19,521,595

27.64%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate xiii

Exercise/Conversion Period xiv

Number of votingrights that may beacquired if theinstrument isexercised/ converted.

% of votingrights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments xv, xvi

Resulting situation after the triggering transaction

Type of financialinstrument

Exercise price

Expiration date xvii

Exercise/Conversion period xviii

Number of voting rights instrument refers to

% of voting rights xix, xx

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

19,521,595

27.64%

9. Chain of controlled undertakings through which the voting rights and/or thefinancial instruments are effectively held, if applicable: xxi

Invesco Asset Management Limited - 19,521,595

Proxy Voting:

10. Name of the proxy holder:

Invesco Ltd.

11. Number of voting rights proxy holder will ceaseto hold:

N/A

12. Date on which proxy holder will cease to holdvoting rights:

N/A

13. Additional information:

14. Contact name:

Philippa Holmes

15. Contact telephone number:

01491 417 447

Note: Annex should only be submitted to the FCA not the issuer

Annex: Notification of major interests in share

A: Identity of the persons or legal entity subject to the notification obligation

Full name

(including legal form of legal entities)

Contact address

(registered office for legal entities)

Phone number & email

Other useful information

(at least legal representative for legal persons)

B: Identity of the notifier, if applicable

Full name

Invesco (UK) Limited

Contact address

Registered Address:

Perpetual Park, Perpetual Park Drive, Henley-on-Thames. Oxon. RG9 1HH

Phone number & email

01491 417 000

Other useful information

(e.g. functional relationship with the person or legal entity subject to the notification obligation)

C: Additional information

For notes on how to complete form TR-1 please see the FCA website.