MRK · Merck & Co., Inc. · Debt

On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Issuer evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Issuer evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Issuer evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Issuer evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Issuer evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Issuer evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Issuer evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.

Supporting evidence: On May 22, 2026, Merck & Co., Inc. (the “Company”) closed an underwritten public offering of $500,000,000 aggregate principal amount of Floating Rate Notes due 2028 (the “Floating Rate Notes”), $1,000,000,000 aggregate principal amount of 4.300% Notes due 2028 (the “2028 Notes”), $500,000,000 aggregate principal amount of 4.650% Notes due 2031 (the “2031 Notes”), $1,000,000,000 aggregate principal amount of 4.950% Notes due 2033 (the “2033 Notes”), $1,500,000,000 aggregate principal amount of 5.200% Notes due 2036 (the “2036 Notes”), $500,000,000 aggregate principal amount of 5.750% Notes due 2046 (the “2046 Notes”) and $1,000,000,000 aggregate principal amount of 5.850% Notes due 2056 (the “2056 Notes” and, together with the Floating Rate Notes, the 2028 Notes, the 2031 Notes, the 2033 Notes, the 2036 Notes and the 2046 Notes, collectively, the “Notes”) under the Company’s Registration Statement on Form S-3ASR (Registration No. 333-278066), originally filed with the Securities and Exchange Commission (the “Commission”) on March 19, 2024, as amended by Post-Effective Amendment No. 1, filed with the Commission on May 14, 2024.