Stock-Based Compensation

9 Months Ended

Jun. 30, 2026

Share-Based Payment Arrangement [Abstract]

Stock-based awards granted in the nine months ended June 30, 2026 and 2025 were granted under the Digi International Inc. 2021 Omnibus Incentive Plan (as amended and restated, the "2021 Plan"). Shares subject to awards under the 2021 Plan or any prior plans that are forfeited, canceled, returned to us for failure to satisfy vesting requirements, settled in cash or otherwise terminated without payment also will be available for grant under the 2021 Plan. The authority to grant options under the 2021 Plan and set other terms and conditions rests with the Compensation Committee of the Board of Directors.

As of June 30, 2026, there were approximately 2,667,883 shares available for future grants under the 2021 Plan.

Cash received from the exercise of stock options was $6.8 million and $3.1 million for the nine months ended June 30, 2026 and 2025, respectively.

Our equity plans and corresponding forms of award agreements generally have provisions allowing employees to elect to satisfy tax withholding obligations through the delivery of shares. When employees make this election, we retain a portion of shares issuable under the award. Tax withholding obligations are otherwise fulfilled by the employee paying cash to us for the withholding. During the nine months ended June 30, 2026 and 2025, our employees forfeited 174,110 shares and 109,516 shares, respectively, in order to satisfy withholding tax obligations of $11.3 million and $3.5 million, respectively. We sponsor an Employee Stock Purchase Plan as amended and restated as of December 10, 2019, October 29, 2013, December 4, 2009 and November 27, 2006 (the "ESPP"), covering all domestic employees with at least 90 days of continuous service and who are customarily employed at least 20 hours per week. The ESPP allows eligible participants the right to purchase common stock on a quarterly basis at the lower of 85% of the market price at the beginning or end of each three-month offering period. The most recent amendments to the ESPP, ratified by our stockholders on January 29, 2020, increased the total number of shares that may be purchased under the ESPP to 3,425,000. ESPP contributions by employees were $2.3 million and $1.7 million for the nine months ended June 30, 2026 and 2025. Pursuant to the ESPP, 61,939 and 70,976 common shares were issued to employees during the nine months ended June 30, 2026 and 2025, respectively. Shares are issued under the ESPP from treasury stock. As of June 30, 2026, 214,764 common shares were available for future issuances under the ESPP.

13. STOCK-BASED COMPENSATION (CONTINUED)

The following table shows stock-based compensation expense that is included in the consolidated results of operations (in thousands):


	Three months ended June 30,				Nine months ended June 30,
	2026		2025		2026		2025
Cost of sales	$	240	$	199	$	675	$	588
Sales and marketing	1,659		1,316		4,722		3,935
Research and development	760		604		1,966		1,761
General and administrative	2,258		1,755		6,048		5,094
Stock-based compensation before income taxes	4,917		3,874		13,411		11,378
Income tax benefit	(1,067)		(836)		(2,897)		(2,437)
Stock-based compensation after income taxes	$	3,850	$	3,038	$	10,514	$	8,941

Stock Options

The following table summarizes our stock option activity (in thousands, except per common share amounts):


	Options Outstanding	Weighted Average Exercise Price	Weighted Average Contractual Term (in years)	Aggregate Intrinsic Value (1)
Balance on September 30, 2025	857	$21.66
Granted	54	41.61
Exercised	(578)	19.70
Forfeited / Canceled	(10)	28.10
Balance on June 30, 2026	323	$28.28	3.7	$	6,443

Exercisable on June 30, 2026	205	$24.36	2.7	$	4,891

(1) The aggregate intrinsic value represents the total pre-tax intrinsic value, based on our closing stock price of $74.95 as of June 30, 2026, which would have been received by the option holders had all option holders exercised their options as of that date.

The intrinsic value of an option is the amount by which the fair value of the underlying stock exceeds its exercise price. The total intrinsic value of all options exercised during the nine months ended June 30, 2026 and 2025 was $16.2 million and $9.6 million, respectively.

The following table shows the weighted average fair value, which was determined based upon the fair value of each option on the grant date utilizing the Black-Scholes option-pricing model and the related assumptions:


	Nine months ended June 30,
	2026	2025
Weighted average per option grant date fair value	$21.20	$16.23
Assumptions used for option grants:
Risk free interest rate	3.62% - 4.16%	4.31% - 4.38%
Expected term	6.00 years	6.00 years
Expected volatility	43% - 49%	48%
Weighted average volatility	49%	48%
Expected dividend yield	—	—

13. STOCK-BASED COMPENSATION (CONTINUED)

The fair value of each option award granted during the periods presented was estimated using the Black-Scholes option valuation model that uses the assumptions noted in the above table. Expected volatilities are based on the historical volatility of our stock. We use historical data to estimate option exercise and employee termination information within the valuation model. The expected term of options granted is derived from the vesting period and historical information and represents the period of time that options granted are expected to be outstanding. The risk-free rate used is the zero-coupon U.S. Treasury bond rate in effect at the time of the grant whose maturity equals the expected term of the option.

As of June 30, 2026, the total unrecognized compensation cost related to non-vested stock options was $1.9 million and the related weighted average period over which it is expected to be recognized is approximately 2.0 years.

Non-vested Stock Units

The following table presents a summary of our non-vested restricted stock units and performance stock units as of June 30, 2026 and changes during the nine months then ended (in thousands, except per common share amounts):


	RSUs			PSUs
	Number of Awards	Weighted Average Grant Date Fair Value		Number of Awards	Weighted Average Grant Date Fair Value
Nonvested on September 30, 2025	966	$	31.99	324	$	31.71
Granted	464	42.08		270	40.90
Vested	(376)	32.60		(83)	32.02
Canceled	(45)	36.92		(40)	40.66
Nonvested on June 30, 2026	1,009	$	36.19	471	$	36.15

As of June 30, 2026, the total unrecognized compensation cost related to non-vested restricted stock units and performance stock units was $28.8 million and $1.6 million, respectively. The related weighted average period over which these costs are expected to be recognized was approximately 2.1 years and 0.3 years, respectively.