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 June, 2006

                               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 on 31 May 2006 that Credit Suisse First Boston, through
its subsidiaries listed below, had a notifiable interest as at 31 May 2006 in
389,899,067 ordinary shares of US$0.50 each in HSBC Holdings plc, representing
approximately 3.40% 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 31 May 2006 from Rob Daborn, Vice President -
Legal and Compliance, Credit Suisse Securities (Europe) Limited

"Dear Sirs,

HSBC Holdings plc ("The Company")

This notification relates to the ordinary shares of the Company ("the shares")
and is given in fulfilment of the obligations imposed under section 198 of the
Companies Act 1985 ("the Act").

We hereby notify you that the Credit Suisse ("CS") companies listed below
(together the "CS companies") hold the following interests in the issued share
capital of the Company:

1.  Credit Suisse Securities (Europe) Limited ("CSSEL") 14,004,262 shares.
    CSSEL held an interest in 2,317,111 of these shares under section 208(5) of
    the act by virtue of the right to redelivery of equivalent securities under
    stock lending arrangements.

2.  Credit Suisse International ("CSi") 204,435 760 shares. CSi held an interest
    in 1,423,014 of these shares under section 208(5) of the act by virtue of
    the right to redelivery of equivalent securities under stock lending
    arrangements.

3.  Credit Suisse Securities (USA) LLC ("CSSLLC") 69,990 shares

4.  Credit Suisse Investment Banking Division ("CSIBD") 1,587,502 shares

5.  Credit Suisse (Hong Kong) Limited ("CSHK") 169,801,553 shares

The CS companies now hold a total interest of 389,899,067 shares being
equivalent to approximately 3.40% of the issued share capital of the Company.

Those Credit Suisse companies which are direct or indirect holding companies of
CSSEL, CSi, CSSLLC, CSIBD and CSHK are, under the terms of section 203 of the
Act, each interested by attribution in any shares in which CSSEL, CSi, CSSLLC,
CSIBD and CSHK are interested.

Yours faithfully,

Rob Daborn

Vice-President - Legal and Compliance"





                                    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:  01 June 2006