v3.25.2
Share-based awards
6 Months Ended
Jun. 30, 2025
Share-Based Payment Arrangement [Abstract]  
Share-based awards Share based awards
Share Options

The following table summarizes option activity for the six months ended June 30, 2025:
 Options
Outstanding
Number of Shares 
Weighted
Average
Exercise
Price
Weighted
Average
Remaining
Contractual
Life
Outstanding at December 31, 2024622,292 $170.52 3.91
Granted118,902 $185.18 
Exercised(58,784)$110.50 
Forfeited/Expired(11,623)$256.00 
Outstanding at June 30, 2025670,787 $176.90 4.30
Exercisable at June 30, 2025436,041 $152.79 3.05

The Company issues ordinary shares for all options exercised. The total amount of fully vested share options which remained outstanding at June 30, 2025 was 436,041. Fully vested share options at June 30, 2025 have an average remaining contractual term of 3.05 years and an average exercise price of $152.79.
Fair value of Stock Options Assumptions

The weighted average fair value of options granted during the six months ended June 30, 2025 and June 30, 2024 was calculated using the Black-Scholes option pricing model. The weighted average grant date fair values and assumptions used were as follows:
Six Months Ended
June 30,
2025
June 30,
2024
Weighted average grant date fair value$64.42 $115.76 
Assumptions: 
Expected volatility35 %36 %
Dividend yield— %— %
Risk-free interest rate4.00 %4.20 %
Expected life4.4 years4.3 years

Expected volatility is based on the historical volatility of our common stock over a period equal to the expected term of the options; the expected life represents the weighted average period of time that options granted are expected to be outstanding given consideration to vesting schedules and our historical experience of past vesting and termination patterns. The risk-free rate is based on the U.S. government zero-coupon bonds yield curve in effect at time of the grant for periods corresponding with the expected life of the option.

Restricted Share Units and Performance Share Units 

On April 23, 2013, the Company adopted the 2013 Employees Restricted Share Unit Plan (the "2013 RSU Plan") pursuant to which the Compensation and Organization Committee of the Company's Board of Directors may make awards under the plan to any employee, Director holding a salaried office or employment with the Company, or a Subsidiary. On May 11, 2015, the 2013 RSU Plan was amended and restated in order to increase the number of shares that can be issued under the RSU Plan by 2.5 million shares. Further, on October 25, 2024, the 2013 RSU Plan was amended and restated effective as of November 6, 2024 in order to increase the number of shares that can be issued under the RSU Plan by a further 2.5 million shares. Accordingly, an aggregate of 6.6 million ordinary shares have been reserved for issuance under the 2013 RSU Plan. The shares are awarded at par value and vest over a service period. Awards under the 2013 RSU Plan may be settled in cash or shares at the option of the Company. No awards may be granted under the 2013 RSU Plan after November 6, 2034.

On April 30 2019, the Company approved the 2019 Consultants and Directors Restricted Share Unit Plan (the “2019 Consultants RSU Plan”), which was effective as of May 16, 2019, pursuant to which the Compensation and Organization Committee of the Company’s Board of Directors may select any consultant, adviser or non-executive Director retained by the Company, or a Subsidiary to receive an award under the plan. 250,000 ordinary shares have been reserved for issuance under the 2019 Consultants RSU Plan. The awards are at par value and vest over a service period. Awards granted to non-executive directors vest over twelve months. No awards may be granted under the 2019 Consultants RSU Plan after May 16, 2029.

    The following table summarizes RSU and PSU activity for the six months ended June 30, 2025:
PSU
Outstanding
Number of
Shares
PSU
Weighted
Average Grant Date
Fair Value
RSU
Outstanding
Number of
Shares
RSU
Weighted
Average Grant Date
Fair Value
Outstanding at December 31, 202419,721 $280.76 647,589 $251.36 
Granted41,359 $185.18 1,145,998 $130.15 
Shares vested(8,191)$231.68 (26,013)$274.54 
Forfeited(11,502)$313.16 (81,914)$239.84 
Outstanding at June 30, 202541,387 $185.96 1,685,660 $169.15 

The fair value of RSUs vested during the six months ended June 30, 2025 totaled $7.1 million (June 30, 2024: $24.3 million). The fair value of RSUs granted during the six months ended June 30, 2025 totaled $149.2 million (June 30, 2024: $75.7 million). Of the fair value of RSUs granted during the six months ended June 30, 2025, $73.9 million (June 30, 2024: $1.5 million) vest over 12 months.

The fair value of PSUs vested during the six months ended June 30, 2025 totaled $1.9 million (June 30, 2024: $1.8 million). The PSUs vest based on service and specified EPS targets over the periods 2022 - 2024, 2023 - 2025, 2024 -
2026 and 2025 - 2027. Depending on the amount of EPS from 2022 to 2027, up to an additional 125,091 PSUs may also be granted.

Stock compensation expense

Stock compensation expense for the three and six months ended June 30, 2025 and June 30, 2024 has been allocated as follows:
Three Months EndedSix Months Ended
June 30,
2025
June 30,
2024
June 30,
2025
June 30,
2024
(in thousands)
Direct costs$9,290 $7,299 $14,671 $14,020 
Selling, general and administrative6,143 7,665 13,056 14,125 
Total$15,433 $14,964 $27,727 $28,145