Company: SNY
Filing Date: 2025-10-29
Form Type: 424B5
Source: 0001193125-25-255563
Chunk: 20

Company: Sanofi
Filing Date: 2025-10-29
Form: 424B5
Chunk 20
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 except as it is a
component of Compounded SOFR. As a result, changes in SOFR may not result in a comparable change in the market value of the floating rate notes.

Any failure of SOFR to maintain market acceptance could adversely affect the floating rate notes.

If SOFR does not maintain market acceptances as a widely used benchmark, the trading price of the floating rate notes may be lower than those
of securities that are linked to rates that are more widely used. Similarly, market terms for floating-rate debt securities linked to SOFR, such as the spread over the base rate reflected in interest rate provisions or the manner of compounding the
base rate, may evolve over time, and trading prices of the floating rate notes may be lower than those of later-issued SOFR-based debt securities as a result. Holders of the floating rate notes may not be able to sell the floating rate notes at all
or may not be able to sell the floating rate notes at prices that will provide them with a yield comparable to similar investments that might have developed greater market acceptance, and may consequently suffer from increased pricing volatility and
market risk.

The interest rate on the floating rate notes is based on a Compounded SOFR rate and the SOFR Index, both of which have a limited history in the marketplace.

For each interest period with respect to the floating rate notes, the interest rate is
based on Compounded SOFR, which is calculated using the SOFR Index published by the Federal Reserve Bank of New York according to the specific formula described under “Description of the Notes—Interest—Floating Rate Notes,”
not the SOFR rate published on or in respect of a particular date during such floating rate notes interest period or an arithmetic average of SOFR rates during such period. For this and other reasons, the interest rate on the floating

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rate notes during any floating rate notes interest period will not be the same as the interest rate on other SOFR-linked investments that use an alternative basis to determine the applicable
interest rate. Further, if the SOFR rate in respect of a particular date during a floating rate notes interest period is negative, its contribution to the SOFR Index will be less than one, resulting in a reduction to Compounded SOFR used to
calculate the interest payable on the floating rate notes on the floating rate interest payment date for such floating rate notes interest period.

Compounded SOFR with respect to a particular interest period will only be capable of being determined near the end of the relevant interest period.