FORM 6-K

                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

                        Report of Foreign Private Issuer
                    Pursuant to Rule 13a - 16 or 15d - 16 of
                      the Securities Exchange Act of 1934

                          For the month of May 2005

                               HSBC Holdings plc

                              42nd Floor, 8 Canada
                        Square, London E14 5HQ, England


(Indicate by check mark whether the registrant files or will file annual
reports under cover of Form 20-F or Form 40-F).

                          Form 20-F X Form 40-F ......

(Indicate by check mark whether the registrant by furnishing the information
contained in this Form is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of
1934).

                                Yes....... No X


(If "Yes" is marked, indicate below the file number assigned to the registrant
in connection with Rule 12g3-2(b): 82- ..............)









NOTIFICATION OF MAJOR INTERESTS IN SHARES

Section 198 - Companies Act 1985

The Company was notified today that Cater Allen International Limited had a
notifiable interest as at 20 May 2005 in 492,112,200 ordinary shares of US$0.50
each in HSBC Holdings plc, representing approximately 4.43% of the ordinary
shares in issue.

A copy of the letter of notification is quoted below.

N S Black

Assistant Secretary

HSBC Holdings plc



Letter to HSBC Holdings plc dated 20 May 2005 from Kevin Whittern, Compliance
Officer, Cater Allen International Limited

"Dear Sir

Notification of Interest in Shares pursuant to Part VI of the Companies Act 1985
(as amended)

In accordance with Part VI of the Companies Act 1985 (as amended), please note
that I have been made aware, as of today the interests of Cater Allen
International Limited (CAIL) in the ordinary shares of HSBC Holdings Plc has
increased to 492,112,200 ordinary shares or 4.43% of the issued share capital.

This holding has arisen from stock loan transactions done under the relevant
approved documentation as a principal trading member of the London Stock
Exchange.



Yours faithfully,





Kevin Whittern

Compliance Officer

Cater Allen International Limited"




                                    SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                               HSBC Holdings plc

                                                By:
                                                Name:  P A Stafford
                                                Title: Assistant Group Secretary
                                                Date:  24 May 2005