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United States Securities and Exchange Commission Washington , D. C. 20549 X ( Mark One ) ANNUAL REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended March 31 , 2021 Ireland ( State or other jurisdiction of incorporation or organization ) TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 ( d ) OF THE SECURITIES EXCHANGE ACT OF 1934 70 Sir John Rogerson's Quay , Dublin 2 , Ireland ( Address of principal executive offices ) FORM 10 - K Title of each class Ordinary Shares , $ 0.001 par value 2.700 % Senior Notes due 2031 3.750 % Senior Notes due 2051 OR Commission file number 001-38848 STERIS plc ( Exact name of registrant as specified in its charter ) Large accelerated filer Non - accelerated filer 353 1 232 2000 ( Registrant's telephone number , including area code ) SECURITIES REGISTERED PURSUANT TO SECTION 12 ( B ) OF THE ACT : Trading symbol ( s ) X STE STE / 31 STE / 51 98-1455064 ( IRS Employer Identification No. ) SECURITIES REGISTERED PURSUANT TO SECTION 12 ( G ) OF THE ACT : None Indicate by check mark if the registrant is a well - known seasoned issuer , as defined in Rule 405 of the Securities Act . Yes x No o Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15 ( d ) of the Act . Yes o No x Indicate by check mark whether the registrant : ( 1 ) has filed all reports required to be filed by Section 13 or 15 ( d ) of the Securities Exchange Act of 1934 during the preceding 12 months ( or for such shorter period that the registrant was required to file such reports ) ; and ( 2 ) has been subject to such filing requirements for the past 90 days . Yes x No o Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S - T ( §232.405 of this chapter ) during the preceding 12 months ( or for such shorter period that the registrant was required to submit such files ) . Yes x No O D02 R296 ( Zip code ) Indicate by check mark whether the registrant is a large accelerated filer , an accelerated filer , a non - accelerated filer , a smaller reporting company , or an emerging growth company . See the definitions of " large accelerated filer , " " accelerated filer , " " smaller reporting company , ” and “ emerging growth company " in Rule 12b - 2 of the Exchange Act . Accelerated filer Smaller reporting company Emerging growth company Name of Exchange on Which Registered New York Stock Exchange New York Stock Exchange New York Stock Exchange 1 0 0 0 If an emerging growth company , indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13 ( a ) of the Exchange Act . O Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial reporting under Section 404 ( b ) of the Sarbanes - Oxley Act ( 15 U.S.C. 7262 ( b ) ) by the registered public accounting firm that prepared or issued its audit report . Indicate by check mark whether the registrant is a shell company ( as defined in Rule 12b - 2 of the Act ) . Yes No X The aggregate market value of Ordinary Shares held by non - affiliates of the registrant as of September , 30 , 2020 was $ 14,957.7 million . The number of Ordinary Shares outstanding as of May 21 , 2021 : 85,369,640 DOCUMENTS INCORPORATED BY REFERENCE Portions of the Proxy Statement for the 2021 Annual Meeting - Part III