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 on 19 May 2005 that Credit Suisse First Boston, through
its subsidiaries listed below, had a notifiable interest as at 17 May 2005 in
684,319,918 ordinary shares of US$0.50 each in HSBC Holdings plc, representing
approximately 6.1% 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 19 May 2005 from Rob Daborn, Vice President,
Equities Compliance, Credit Suisse First Boston (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 on 17 May 2005, following acquisitions, CSFB (as
defined below) holds the following interests in the issued share capital of the
Company:

 1. Credit Suisse First Boston (Europe) Limited ("CSFBEL"): has an interest in
    55,871,394 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 First Boston International ("CSFBi"): 297,894,079 shares.
 3. Credit Suisse First Boston (Hong Kong) Limited ("CSFBHK"): 330,553,095
    shares.
 4. Credit Suisse First Boston Capital LLC("CSFBC") 1,350 shares

CSFB now holds a total interest of 684,319,918 shares being equivalent to
approximately 6.1% of the issued share capital of the Company.

CSFBEL, CSFBI, CSFBC and CSFBHK are members of the investment banking business
of Credit Suisse and reference to CSFB in this letter includes all of the
subsidiaries and affiliates of Credit Suisse operating under the Credit Suisse
First Boston name. Those CSFB companies, which are direct or indirect holding
companies of CSFBEL, CSFBI, CSFBC and CSFBHK are under the terms of section 203
of the Act, each interested by attribution in any shares in which CSFBEL,CSFBI,
CSFBI, CSFBC and CSFBHK are interested.



Yours faithfully

Rob Daborn

Vice President - Equities 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:  20 May 2005