The carrying amounts of our senior convertible notes were as follows:



(In millions)	September 30, 2026		December 31, 2025
Principal amount:

2028 Notes	$	1,250.0	$	1,250.0

Unamortized debt issuance costs	(6.3)		(9.1)
Carrying amount of senior convertible notes	$	1,243.7	$	1,240.9

The following table summarizes the components of interest expense and the effective interest rates for our senior convertible notes:



	Three Months Ended September 30,						Nine Months Ended September 30,
(In millions)	2026			2025			2026			2025
Cash interest expense:
Contractual coupon interest (1)	$	1.1		$	1.9		$	3.5		$	5.8
Non-cash interest expense:
Amortization of debt issuance costs	1.0			1.8			2.9			5.4
Total interest expense recognized on senior notes	$	2.1		$	3.7		$	6.4		$	11.2

Effective interest rate:
2025 Notes	*			0.5		%	*			0.5		%
2028 Notes	0.7		%	0.7		%	0.7		%	0.7		%

(1) Interest on the 2025 Notes began accruing upon issuance and was payable semi-annually on May 15 and November 15 of each year until the 2025 Notes matured in November 2025. Interest on the 2028 Notes began accruing upon issuance and is payable semi-annually on May 15 and November 15 of each year.

* Not applicable as no notes were outstanding in the relevant period.

The fair value, based on trading prices (Level 1 inputs), of our senior convertible notes were as follows:



	Fair Value Measurements Using Level 1
(In millions)	September 30, 2026		December 31, 2025

2028 Notes	$	1,185.5	$	1,152.1

The following table summarizes key details of the 2028 Notes:

Senior Convertible Notes

Offering Completion Date

Maturity Date

Stated Interest Rate

Aggregate Principal Amount Issued

Net Proceeds(1)

Initial Conversion Rate(2)

(per $1,000 principal amount)

Conversion Price

(per share)

Settlement Methods(3)

2028 Notes

May 2023

May 15, 2028

0.375%

$1.25 billion

$1.23 billion

6.1571 shares

$162.41

Cash and/or shares

(1) Net proceeds are calculated by deducting the initial purchasers’ discounts and estimated costs directly related to the offering from the aggregate principal amount of the applicable series of notes.

(2) Subject to adjustments as defined in the applicable indentures.

(3) The 2028 Notes may be settled upon conversion in cash, stock, or a combination thereof, solely at our discretion.

The following table outlines the conversion options related to our 2028 Notes:


Summary of Conversions Rights at the Option of the Holders for the 2028 Notes, or the Notes

Conversion Rights at the Option of the Holders						Holders of the Notes have the ability to convert all or a portion of their notes in multiples of $1,000 principal amount, at their option prior to 5:00 p.m., New York City time, on the business day immediately preceding February 15, 2028 for the 2028 Notes only under the following circumstances:


Circumstance 1(1)						During any calendar quarter commencing after the applicable period (and only during such calendar quarter), if the last reported sale price of Dexcom’s common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the applicable conversion price for the Notes on each applicable trading day


Circumstance 2						During the five business day period after any five consecutive trading day period in which the trading price per $1,000 principal amount of the Notes for each trading day of that five consecutive trading day period was less than 98% of the product of the last reported sale price of Dexcom’s common stock and the applicable conversion rate of the Notes on each such trading day


Circumstance 3						If we call any or all of the Notes for redemption, at any time prior to the close of business on the scheduled trading day immediately preceding the redemption date (only with respect to the notes called or deemed called for redemption)


Circumstance 4						Upon the occurrence of specified corporate events


Circumstance 5(2)						Holders of the Notes may convert all or a portion of their notes regardless of the foregoing circumstances prior to the close of business on the second scheduled trading day immediately preceding the maturity date


(1) Circumstance 1 is available after the calendar quarter ended September 30, 2023 for the 2028 Notes.
(2) Circumstance 5 is available on or after February 15, 2028 for the 2028 Notes.


Summary of Conversion Right at the Option of the Company for the 2028 Notes

Conversion Right at Our Option(1)						Dexcom may redeem for cash all or part of the Notes, at its option, if the last reported sale price of our common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period ending on, and including, the trading day immediately preceding the date on which Dexcom provides notice of redemption. The redemption price will be equal to 100% of the principal amount of the Notes to be redeemed plus accrued and unpaid interest to, but excluding, the redemption date


(1) Dexcom does not have the right to redeem the 2028 Notes prior to May 20, 2026. Dexcom has the right to redeem the 2028 Notes on or after May 20, 2026 and prior to February 15, 2028.