Ciena Set to Join S&P 500; Arrowhead Pharmaceuticals to Join S&P MidCap 400; ADT and OneSpaWorld Holdings to Join S&P SmallCap 600

S&P Dow Jones Indices will make the following changes to the S&P 500, S&P MidCap 400, S&P SmallCap 600:

— S&P MidCap 400 constituent Ciena Corp. (NYSE: CIEN) will replace Dayforce Inc. (NYSE: DAY) in the S&P 500, S&P SmallCap 600 constituent Arrowhead Pharmaceuticals Inc. (NASD: ARWR) will replace Ciena in the S&P MidCap 400, and ADT Inc. (NYSE: ADT) will replace Arrowhead Pharmaceuticals in the S&P SmallCap 600 effective prior to the opening of trading on Monday, February 9. Thoma Bravo L.P. acquired Dayforce in a deal that closed today.

— OneSpaWorld Holdings Ltd. (NASD: OSW) will replace Dynavax Technologies Corp. (NASD: DVAX) in the S&P SmallCap 600 effective prior to the opening of trading on Tuesday, February 10. Sanofi is acquiring Dynavax Technologies in a deal expected to be completed soon pending final closing conditions.

Following is a summary of the changes that will take place prior to the open of trading on the effective date:

Effective Date Index Name Action Company Name Ticker GICS Sector Feb 9, 2026 S&P 500 Addition Ciena CIEN Information Technology Feb 9, 2026 S&P 500 Deletion Dayforce DAY Industrials Feb 9, 2026 S&P MidCap 400 Addition Arrowhead Pharmaceuticals ARWR Health Care Feb 9, 2026 S&P MidCap 400 Deletion Ciena CIEN Information Technology Feb 9, 2026 S&P SmallCap 600 Addition ADT ADT Consumer Discretionary Feb 9, 2026 S&P SmallCap 600 Deletion Arrowhead Pharmaceuticals ARWR Health Care Feb 10, 2026 S&P SmallCap 600 Addition OneSpaWorld Holdings OSW Consumer Discretionary Feb 10, 2026 S&P SmallCap 600 Deletion Dynavax Technologies DVAX Health Care

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SOURCE S&P Dow Jones Indices

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