Holding(s) in Company

TR-1: NOTIFICATION OF MAJOR INTEREST IN SHARES

1. Identity of the issuer or the underlying issuer of existing shares to which voting rights are attached:

Development Securities PLC

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

An acquisition or disposal of voting rights

Yes

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):

No

3. Full name of person(s) subject to the notification obligation:

Ameriprise Financial, Inc. and its group

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

See additional information under 13.

5. Date of the transaction and date on which the threshold is crossed or reached:

16 March 2011

6. Date on which issuer notified:

18 March 2011

7. Threshold(s) that is/are crossed or reached:

Above the threshold of 5%

8. Notified details:

A: Voting rights attached to shares

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

Direct

Direct

Indirect

Direct

Indirect

GB0002668464

N/A

N/A

183,102

183,102

5,991,274

0.150%

4.896%

B: Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Expirationdate

Exercise/ConversionPeriod

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

% of votingrights

C: Financial Instruments with similar economic effect to Qualifying Financial Instruments

Resulting situation after the triggering transaction

Type of financialinstrument

Exerciseprice

Expirationdate

Exercise/Conversionperiod

Number of votingrights instrumentrefers to

% of voting rights

Nominal

Delta

Total (A+B+C)

Number of voting rights

Percentage of voting rights

6,174,376

5.046%

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

Ameriprise Financial, Inc, which through intermediate holding companies controls the voting rights of Columbia Management Investment Advisers, Columbia Wanger Asset Management, Threadneedle Management Luxembourg SA and Threadneedle Asset Management Holdings Ltd, which itself controls the voting rights of Threadneedle Asset Management Ltd, Threadneedle International Ltd and Threadneedle Pensions Ltd.

Proxy Voting:

10. Name of the proxy holder:

N/A

11. Number of voting rights proxy holder will cease to hold:

N/A

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

N/A

13. Additional information:

Registered Owner

Ameriprise Financial Inc

A/c

123,771

Littledown Nominees Ltd

A/c ZLA05

385,361

Littledown Nominees Ltd

A/c ZLA07

4,039,406

Littledown Nominees Ltd

A/c 07197

183,102

Littledown Nominees Ltd

A/c 10479

2,887

Littledown Nominees Ltd

A/cZLA12

139,578

Littledown Nominees Ltd

A/c ZLA14

38,710

Littledown Nominees Ltd

A/c 34789

338,943

Littledown Nominees Ltd

A/C 10488

922,618

14. Contact name:

Stacey Dryburgh, Threadneedle group

15. Contact telephone number:

+44(0)1793 363751