Assystem

Transaction in Own Shares • Jan 9, 2026

HALF-YEAR LIQUIDITY CONTRACT STATEMENT

Paris, January 9 th, 2026

Under the liquidity contract entered between ASSYSTEM S.A. (ISIN: FR0000074148 - ASY) and Kepler Cheuvreux, the following resources appeared on the liquidity account on December 31st, 2025:

• 10,903 shares
• € 842,698.88
• Number of executions on buy side on semester: 1,520
• Number of executions on sell side on semester: 1,528
• Traded volume on buy side on semester: 43,079 shares for € 1,872,571.29
• Traded volume on sell side on semester: 43,617 shares for € 1,908,637.73

As a reminder:

• the following resources appeared on the last half year statement on June 30th , 2025, on the liquidity account:
• 11,441 shares
• € 802,309.97
• Number of executions on buy side on semester: 2,444
• Number of executions on sell side on semester: 2,323
• Traded volume on buy side on semester: 80,317 shares for € 3,114,213.43
• Traded volume on sell side on semester: 76,852 shares for € 2,992,189.41
• the following resources appeared on the liquidity account when the activity started:
• 22,970 shares
• € 923,444.41

The liquidity agreement complies with AMF Decision n° 2021-01 dated on June 22nd , 2021, introducing liquidity agreements on equity securities as permitted market practice.

ABOUT ASSYSTEM

Assystem, one of the world's leading independent nuclear engineering companies, is committed to accelerating the energy transition. With 60 years of experience in highly regulated sectors with stringent safety and security constraints, the Group provides engineering and project management services as well as digital solutions and services to optimise the performance of complex infrastructure assets throughout their life cycle.

In its 13 countries of operation, Assystem's 8,000 experts are supporting energy transition. To achieve an affordable low carbon energy supply, Assystem is committed to the development of low carbon electricity (nuclear, renewables and electricity grids) and clean hydrogen. The Group is also helping drive the use of low carbon electricity in industrial sectors such as transportation.

Assystem is currently ranked among the top three nuclear engineering groups worldwide.

Assystem forms part of the Euronext Tech Leaders, CAC Small, CAC Mid & Small, CAC Industrials, CAC All-Tradable and CAC All-Share indices.

To find out more visit www.assystem.com

CONTACT Malène Korvin CFO

Tél : +33 (0)1 41 25 29 00

Buy Side Sell Side Number of Number of Traded volume in Number of Number of Traded volume in executions shares EUR executions shares EUR Total 1,520 43,079 1,872,571.29 1,528 43,617 1,908,637.73 07/01/2025 13 477 19,871.82 4 114 4,774.32 07/02/2025 22 567 23,405.76 37 907 37,658.64 07/03/2025 2 100 4,225.00 15 329 13,956.18 07/04/2025 6 245 10,319.40 5 150 6,349.50 07/07/2025 29 634 26,621.66 13 356 15,037.44 07/08/2025 11 500 20,585.00 8 803 33,099.66 07/09/2025 3 100 4,235.00 17 597 25,426.23 07/10/2025 5 200 8,490.00 - - - 07/11/2025 19 550 23,463.00 24 750 32,047.50 07/14/2025 37 1,255 53,776.75 22 1,305 55,997.55 07/15/2025 20 450 19,345.50 26 1,001 43,273.23 07/16/2025 20 500 21,805.00 3 150 6,640.50 07/17/2025 8 250 10,880.00 17 600 26,268.00 07/18/2025 18 567 24,840.27 12 450 19,795.50 07/21/2025 20 633 27,763.38 14 570 25,051.50 07/22/2025 10 251 10,953.64 8 221 9,699.69 07/23/2025 8 334 14,645.90 29 709 31,224.36 07/24/2025 4 200 8,916.00 16 600 27,018.00 07/25/2025 8 300 14,364.00 35 1,150 55,395.50 07/28/2025 17 650 31,135.00 12 450 21,694.50 07/29/2025 10 400 19,272.00 19 450 21,789.00 07/30/2025 3 150 7,260.00 11 300 14,550.00 07/31/2025 12 250 12,105.00 11 270 13,130.10 08/01/2025 18 450 21,465.00 2 71 3,412.26 08/04/2025 16 500 23,225.00 12 250 11,655.00 08/05/2025 2 100 4,640.00 14 351 16,507.53 08/06/2025 10 202 9,534.40 14 399 18,932.55 08/07/2025 2 9 432.27 5 229 11,017.19 08/08/2025 15 390 18,614.70 8 150 7,185.00 08/11/2025 12 502 23,970.50 15 281 13,558.25 08/12/2025 8 200 9,470.00 9 250 11,925.00 08/13/2025 21 650 31,453.50 18 580 28,251.80 08/14/2025 10 300 14,454.00 21 650 31,408.00 08/15/2025 19 450 21,712.50 13 402 19,472.88 08/18/2025 4 100 4,810.00 2 100 4,845.00 08/19/2025 1 1 48.40 13 398 19,513.94 08/20/2025 15 500 23,880.00 - - - 08/21/2025 7 200 9,620.00 2 150 7,270.50 08/22/2025 2 50 2,400.00 10 350 16,954.00 08/25/2025 21 600 28,902.00 20 500 24,170.00 08/26/2025 37 1,099 50,861.72 15 350 16,324.00 08/27/2025 7 300 13,854.00 5 200 9,268.00 08/28/2025 11 300 13,776.00 5 250 11,545.00 08/29/2025 12 450 20,371.50 3 150 6,900.00 09/01/2025 3 50 2,280.00 8 400 18,264.00 09/02/2025 15 450 20,241.00 - - - 09/03/2025 16 330 14,543.10 1 5 220.75 09/04/2025 - - - 6 295 13,047.85 09/05/2025 9 350 15,596.00 11 231 10,316.46 09/08/2025 9 350 15,550.50 14 469 20,936.16 09/09/2025 9 335 15,081.70 11 350 15,767.50 09/10/2025 3 115 5,175.00 5 100 4,525.00 09/11/2025 1 1 44.60 9 300 13,635.00 09/12/2025 1 50 2,310.00 10 327 15,189.15 09/15/2025 8 250 11,700.00 13 373 17,527.27 09/16/2025 15 351 16,212.69 - - - 09/17/2025 63 1,880 80,633.20 32 1,153 50,028.67 09/18/2025 22 381 16,863.06 16 515 22,829.95 09/19/2025 11 250 11,095.00 10 282 12,619.50 09/22/2025 17 650 28,327.00 9 351 15,352.74 09/23/2025 20 400 17,004.00 4 150 6,469.50 09/24/2025 6 150 6,385.50 9 350 14,948.50 09/25/2025 4 200 8,560.00 7 251 10,782.96 09/26/2025 5 200 8,660.00 7 249 10,826.52 09/29/2025 11 300 12,807.00 - - - 09/30/2025 5 200 8,470.00 12 300 12,780.00 10/01/2025 16 501 21,422.76 12 351 15,089.49 10/02/2025 17 500 21,160.00 27 750 31,972.50 10/03/2025 15 470 19,913.90 6 150 6,480.00 10/06/2025 12 650 26,851.50 21 401 16,681.60 10/07/2025 4 150 6,240.00 6 98 4,113.06 10/08/2025 22 500 20,745.00 14 521 21,663.18 10/09/2025 19 505 20,932.25 18 393 16,348.80 10/10/2025 24 650 26,624.00 13 274 11,318.94

10/13/2025	8	364	14,843.92	29	666	27,292.68
10/14/2025	16	481	19,538.22	4	100	4,073.00
10/15/2025	3	100	4,070.00	12	252	10,314.36
10/16/2025	8	351	14,320.80	12	348	14,264.52
10/17/2025	15	499	19,940.04	6	100	4,010.00
10/20/2025	7	213	8,558.34	19	350	14,108.50
10/21/2025	10	156	6,274.32	17	250	10,140.00
10/22/2025	11	550	22,495.00	25	573	23,493.00
10/23/2025	-	-	-	16	823	33,956.98
10/24/2025	9	600	24,774.00	10	300	12,519.00
10/27/2025	6	250	10,490.00	20	311	13,077.55
10/28/2025	8	246	10,302.48	5	56	2,353.68
10/29/2025	-	-	-	30	582	25,095.84
10/30/2025	11	450	19,467.00	16	356	15,407.68
10/31/2025	-	-	-	24	335	14,592.60
11/03/2025	19	700	30,380.00	18	550	23,925.00
11/04/2025	18	504	21,304.08	-	-	-
11/05/2025	6	201	8,251.05	2	2	83.20
11/06/2025	14	208	8,490.56	4	153	6,256.17
11/07/2025	15	472	19,045.20	12	352	14,287.68
11/10/2025	7	200	8,096.00	12	196	7,987.00
11/11/2025	8	150	6,139.50	18	449	18,480.84
11/12/2025	4	150	6,270.00	8	200	8,380.00
11/13/2025	21	302	12,635.68	5	205	8,601.80
11/14/2025	14	248	10,207.68	7	159	6,584.19
11/17/2025	3	7	294.00	9	286	12,014.86
11/18/2025	15	443	18,477.53	10	359	15,124.67
11/19/2025	16	454	18,927.26	7	349	14,612.63
11/20/2025	29	567	23,796.99	15	504	21,218.40
11/21/2025	30	442	18,219.24	10	277	11,489.96
11/24/2025	15	387	15,607.71	16	490	20,090.00
11/25/2025	13	296	12,159.68	22	395	16,333.25
11/26/2025	3	50	2,080.00	1	34	1,428.00
11/27/2025	8	343	14,399.14	29	992	41,921.92
11/28/2025	8	202	8,623.38	11	270	11,553.30
12/01/2025	29	312	13,303.68	13	350	15,004.50
12/02/2025	8	198	8,508.06	7	200	8,626.00
12/03/2025	8	250	10,765.00	2	100	4,323.00
12/04/2025	7	147	6,345.99	17	258	11,153.34
12/05/2025	7	110	4,787.20	11	143	6,236.23
12/08/2025	6	143	6,176.17	16	328	14,372.96
12/09/2025	20	402	17,728.20	9	207	9,234.27
12/10/2025	11	299	12,824.11	-	-	-
12/11/2025	5	137	5,829.35	2	100	4,295.00
12/12/2025	15	600	25,548.00	13	359	15,458.54
12/15/2025	14	300	12,408.00	30	550	23,226.50
12/16/2025	1	1	43.00	5	200	8,610.00
12/17/2025	17	299	12,677.60	4	65	2,795.00
12/18/2025	9	108	4,502.52	8	151	6,311.80
12/19/2025	10	201	8,349.54	9	200	8,340.00
12/22/2025	10	255	10,485.60	11	300	12,444.00
12/23/2025	6	150	6,229.50	12	200	8,356.00
12/24/2025	4	71	2,939.40	4	59	2,454.40
12/29/2025	4	124	5,087.72	-	-	-
12/30/2025	13	252	10,321.92	11	292	12,068.36
	1	49	2,028.60	8	249	10,527.72