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 November, 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 27 November 2006 that Merrill Lynch & Co., Inc. had a notifiable interest as at 27 November 2006 in 515,386,875 ordinary shares of US$0.50 each in HSBC Holdings plc, representing approximately 4.45% of the ordinary shares in issue. A copy of the letter of the notification is quoted below. P A Stafford Deputy Group Company Secretary HSBC Holdings plc Letter to HSBC Holdings plc dated 27 November 2006 from Merrill Lynch International "Dear Sir Companies Act 1985 ss 198-202 (as amended) We are writing to notify you with regard to a change of circumstances affecting Merrill Lynch & Co., Inc's interest under the above legislation. This letter serves as notification, by reason of the provisions of section 203 of the above Act, that: a) BlackRock Inc. (as asset management company in which Merrill Lynch & Co., Inc owns 49.8% of the common stock) has the interests in relevant share capital of your company disclosed in the attachments to this letter; b) Merrill Lynch & Co., Inc has in aggregate the interests in the relevant share capital of your company disclosed in the attachment to this letter. If you have any queries regarding the contents of this letter, please contact Alasdair Coutts-Britton on 020-7996-3565, Facsimile 020-7996-1174. Yours faithfully (signed) Duly authorised for and on behalf of The notifying companies Attachment Company: HSBC Holdings Plc as of: 17 November 2006 Class of shares: ordinary Each company named below is interested in the aggregate number of the shares identified above set opposite its name. Where the number includes shares additional to those shown in the first attachment to the accompanying letter, certain further details are also set out below. Company Aggregate number of shares interested in Merrill Lynch & Co., Inc 377,454,454 BlackRock Group 137,932,421 Aggregated total 515,386,875 Schedule Part 1 Name Address BlackRock Investment 33 King William Street Management (UK) Limited London EC4R 9AS Part 2 Merrill Lynch & Co., Inc. World Financial Center North Tower 250 Vesey Street New York NY 10281-1332" 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: 28 November, 2006