Barclays PLC — Capital/Financing Update 2021

Aug 2, 2021

Supplement Number 1 dated 2 August 2021 to the Base Prospectus dated 7 May 2021

BARCLAYS BANK PLC

(incorporated with limited liability in England and Wales)

as Issuer

£15,000,000,000 Debt Issuance Programme

This base prospectus supplement (the "Supplement") is supplemental to, forms part of and must be read in conjunction with, the base prospectus dated 7 May 2021 (the "Base Prospectus") prepared by Barclays Bank PLC (the "Issuer") with respect to its £15,000,000,000 Debt Issuance Programme (the "Programme"). This Supplement constitutes a supplementary prospectus in respect of the Base Prospectus for the Issuer for the purposes of Article 23 of Regulation (EU) 2017/1129 of the European Parliament and of the Council of 14 June 2017 as it forms part of domestic law of the United Kingdom by virtue of the European Union (Withdrawal) Act 2018, as amended (the " UK Prospectus Regulation").

Terms defined in the Base Prospectus shall, unless the context otherwise requires, have the same meaning when used in this Supplement.

This Supplement has been approved by the United Kingdom Financial Conduct Authority (the "FCA"), as competent authority under the UK Prospectus Regulation. The FCA only approves this Supplement as meeting the standards of completeness, comprehensibility and consistency imposed by the UK Prospectus Regulation. Such approval should not be considered as an endorsement of the Issuer that is the subject of this Supplement. With effect from the date of this Supplement the information appearing in, or incorporated by reference into, the Base Prospectus shall be supplemented in the manner described below.

The purpose of this Supplement is to:

• (a) supplement the information set out in the section entitled "Information Incorporated by Reference" commencing on page 14 of the Base Prospectus, and additionally incorporate by reference into the Base Prospectus:
• the Supplement 1/2021 to the Registration Document dated 30 July 2021 ("Supplement 1/2021"); and
• the unaudited Interim Results Announcement of the Issuer, as filed with the SEC on Form 6-K (including exhibits thereto) on 28 July 2021 in respect of the six months ended 30 June 2021 (the "Interim Results Announcement").

The Interim Results Announcement is available in electronic form at https://home.barclays/content/dam/home-barclays/documents/investorrelations/ResultAnnouncements/H12021/20210728-BBPLC-H12021-6-K-2021.pdf.

Supplement 1/2021 and the Interim Results Announcement have each been filed with the FCA and shall be deemed to be incorporated in, and form part of, the Base Prospectus as supplemented by this Supplement. Supplement 1/2021 and the Interim Results Announcement may be inspected during normal business hours at Barclays Treasury, 1 Churchill Place, London, E14 5HP, United Kingdom and at the specified office of the Principal Paying Agent, at One Canada Square, London, E14 5AL, United Kingdom during the life of the Notes issued pursuant to the Base Prospectus. They are also available in electronic form at https://www.home.barclays/barclays-investor-relations.html. The Interim Results Announcement has also been filed with the SEC and is available in electronic form on the SEC's website at https://www.sec.gov/cgibin/browse-edgar?company=barclays+bank+plc&owner=exclude&action=getcompany;

• (b) amend the section entitled "Information Incorporated by Reference" on page 14 of the Base Prospectus by deleting the words "endorsed by the UK" and replacing such text with "adopted by the UK";
• (c) replace the second paragraph of information in the section entitled "Forward-Looking Statements" commencing on page vii of the Base Prospectus with the following updated information:

"By their nature, forward-looking statements involve risk and uncertainty because they relate to future events and circumstances. The forward-looking statements speak only as at the date on which they are made. Forward-looking statements may be affected by changes in legislation, the development of standards and interpretations under IFRS, including evolving practices with regard to the interpretation and application of accounting and regulatory standards, the outcome of current and future legal proceedings and regulatory investigations, future levels of conduct provisions, the policies and actions of governmental and regulatory authorities, the Group's ability along with governments and other stakeholders to measure, manage and mitigate the impacts of climate change effectively, geopolitical risks and the impact of competition. In addition, factors including (but not limited to) the following may have an effect: capital, leverage and other regulatory rules applicable to past, current and future periods; UK, United States ("U.S."), Eurozone and global macroeconomic and business conditions; the effects of any volatility in credit markets; market related risks such as changes in interest rates and foreign exchange rates; effects of changes in valuation of credit market exposures; changes in valuation of issued securities; volatility in capital markets; changes in credit ratings of any entity within the Barclays Bank Group or any securities issued by such entities; direct and indirect impacts of the coronavirus ("COVID-19") pandemic; instability as a result of the UK's exit from the European Union (the "EU"), the effects of the EU-UK Trade and Cooperation Agreement and the disruption that may subsequently result in the UK and globally; the risk of cyber-attacks, information or security breaches or technology failures on the Group's reputation, business or operations; and the success of future acquisitions, disposals and other strategic transactions. A number of these influences and factors are beyond the Barclays Bank Group's control. As a result, the Barclays Bank Group's actual financial position, future results, capital distributions, capital, leverage or other regulatory ratios or other financial and non-financial metrics or performance measures may differ materially from the statements or guidance set forth in the Barclays Bank Group's forwardlooking statements. Additional risks and factors which may impact the Barclays Bank Group's future financial condition and performance are identified in the Barclays Bank Group's filings with the SEC (including, without limitation, in the 20-F and the Interim Results Announcement), which are available on the SEC's website at http://www.sec.gov.";

(d) amend the sub-section entitled "Risk Factors - Risks relating to the Issuer and the Barclays Bank Group" on page 6 of the Base Prospectus by deleting it in its entirety and replacing it with the following:

"Risks relating to the Issuer and the Barclays Bank Group

Prospective investors should consider the section entitled "Risk Factors" on pages 1-21 of the Registration Document (defined below) and pages 2 to 3 of Supplement 1/2021 (as defined below) to the Registration Document which are referred to in, and incorporated by reference into, this Base Prospectus as set out in, "Information Incorporated by Reference" on page 14 of this Base Prospectus.";

(e) amend the section entitled "The Issuer, the Barclays Bank Group and the Group" on page 101 of the Base Prospectus by deleting it in its entirety and replacing it with the following:

"THE ISSUER, THE BARCLAYS BANK GROUP AND THE GROUP

For information in respect of the Issuer, the Barclays Bank Group and the Group, prospective investors are referred to the section entitled "The Issuer, the Barclays Bank Group and the Group" on pages 24 to 26 of the Registration Document and pages 3 to 4 of Supplement 1/2021, which are referred to in, and incorporated by reference into, this Base Prospectus as set out in, "Information Incorporated by Reference" on page 14 of this Base Prospectus.".

IMPORTANT NOTICES

The Issuer accepts responsibility for the information contained in this Supplement and declares that, to the best of its knowledge, the information contained in this Supplement is in accordance with the facts and this Supplement makes no omission likely to affect its import.

To the extent that there is any inconsistency between (a) any statement in this Supplement or any statement incorporated by reference into the Base Prospectus by this Supplement and (b) any other statement in, or incorporated by reference into, the Base Prospectus, the statements in (a) above will prevail.

Save as disclosed in this Supplement, no significant new factor, material mistake or material inaccuracy relating to the information included in the Base Prospectus which is capable of affecting the assessment of the Notes issued under the Programme has arisen or been noted, as the case may be, since the publication of the Base Prospectus.

Any information contained in the documents specified above which is not incorporated by reference in the Base Prospectus is either not relevant for prospective investors for the purposes of Article 6(1) of the UK Prospectus Regulation or is covered elsewhere in the Base Prospectus.

If documents which are incorporated by reference into this Supplement themselves incorporate any information or other documents therein, either expressly or implicitly, such information or other documents will not form part of this Supplement for the purposes of the UK Prospectus Regulation except where such information or other documents are specifically incorporated by reference into this Supplement.

This Supplement shall be available on or around the date hereof in electronic form at http://www.londonstockexchange.com/exchange/news/market-news/market-news-home.html.

2 August 2021