Matthew Scott Harris

Insider

First SEC filing: Feb. 3, 2021 · Latest: Feb. 3, 2021

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Insider at Companies where this person is a reporting insider.
Insider transactions Every share this person bought or sold, from Form 4 filings.
Derivatives Options and other derivative holdings reported by this person.
Compensation Executive pay disclosed in company proxy statements.

Insider at

ALT buying March 23, 2023

Insider transactions

0 buys (P) 0 sells (S) Net: $0 + 56 non-open-market transactions below last 12 months, based on the transactions shown below

Price change vs current quote, split-adjusted for corporate actions since the filing — not benchmarked, not annualized, not size-weighted

56 other filings hidden

Date	Ticker	Code	Shares	Price	Value	Owned after	Δ own	A/D	vs now
July 31, 2025	ALT	A	2,018	$3.14	$6,337	16,087 Direct	+14.34%	Acquired	-3.8% (price as of 2026-08-20)
March 7, 2025	ALT	G	67,787	—	—	14,069 Direct	-82.81%	Disposed	(price as of 2026-08-20)
Feb. 2, 2025	ALT	M	7,775	—	—	7,775 Direct	—	Acquired	(price as of 2026-08-20)
Feb. 2, 2025	ALT	F	2,708	$6.64	$17,981	81,856 Direct	-3.20%	Disposed	-54.5% (price as of 2026-08-20)
Feb. 2, 2025	ALT	M	7,775	—	—	84,564 Direct	+10.13%	Acquired	(price as of 2026-08-20)
Feb. 1, 2025	ALT	M	6,166	—	—	0 Direct	—	Acquired	(price as of 2026-08-20)
Feb. 1, 2025	ALT	F	2,109	$6.64	$14,004	76,789 Direct	-2.67%	Disposed	-54.5% (price as of 2026-08-20)
Feb. 1, 2025	ALT	M	6,166	—	—	78,898 Direct	+8.48%	Acquired	(price as of 2026-08-20)
Jan. 31, 2025	ALT	A	1,905	$5.18	$9,868	72,732 Direct	+2.69%	Acquired	-41.7% (price as of 2026-08-20)
Jan. 30, 2025	ALT	M	9,275	—	—	18,550 Direct	+100.00%	Acquired	(price as of 2026-08-20)
Jan. 30, 2025	ALT	F	3,173	$7.00	$22,211	70,827 Direct	-4.29%	Disposed	-56.9% (price as of 2026-08-20)
Jan. 30, 2025	ALT	M	9,275	—	—	74,000 Direct	+14.33%	Acquired	(price as of 2026-08-20)
Jan. 27, 2025	ALT	A	63,400	—	—	63,400 Direct	—	Acquired	(price as of 2026-08-20)
Jan. 27, 2025	ALT	A	183,600	—	—	183,600 Direct	—	Acquired	(price as of 2026-08-20)
Jan. 25, 2025	ALT	M	14,600	—	—	43,800 Direct	+50.00%	Acquired	(price as of 2026-08-20)
Jan. 25, 2025	ALT	F	4,994	$6.98	$34,858	64,725 Direct	-7.16%	Disposed	-56.7% (price as of 2026-08-20)
Jan. 25, 2025	ALT	M	14,600	—	—	69,719 Direct	+26.49%	Acquired	(price as of 2026-08-20)
July 31, 2024	ALT	A	1,486	$5.41	$8,039	55,119 Direct	+2.77%	Acquired	-44.2% (price as of 2026-08-20)
Feb. 2, 2024	ALT	M	7,775	—	—	15,550 Direct	-33.33%	Disposed	(price as of 2026-08-20)
Feb. 2, 2024	ALT	F	2,332	$9.32	$21,734	53,633 Direct	-4.17%	Disposed	-67.6% (price as of 2026-08-20)
Feb. 2, 2024	ALT	M	7,775	—	—	55,965 Direct	+16.13%	Acquired	(price as of 2026-08-20)
Feb. 1, 2024	ALT	M	6,166	—	—	6,166 Direct	-50.00%	Disposed	(price as of 2026-08-20)
Feb. 1, 2024	ALT	F	1,801	$9.88	$17,794	48,190 Direct	-3.60%	Disposed	-69.4% (price as of 2026-08-20)
Feb. 1, 2024	ALT	M	6,166	—	—	49,991 Direct	+14.07%	Acquired	(price as of 2026-08-20)
Jan. 31, 2024	ALT	A	3,257	$2.69	$8,761	43,825 Direct	+8.03%	Acquired	12.3% (price as of 2026-08-20)
Jan. 30, 2024	ALT	M	9,275	—	—	27,825 Direct	-25.00%	Disposed	(price as of 2026-08-20)
Jan. 30, 2024	ALT	F	2,709	$9.80	$26,548	40,568 Direct	-6.26%	Disposed	-69.2% (price as of 2026-08-20)
Jan. 30, 2024	ALT	M	9,275	—	—	43,277 Direct	+27.28%	Acquired	(price as of 2026-08-20)
Jan. 25, 2024	ALT	A	58,400	—	—	58,400 Direct	—	Acquired	(price as of 2026-08-20)
Jan. 25, 2024	ALT	A	163,200	—	—	163,200 Direct	—	Acquired	(price as of 2026-08-20)
July 31, 2023	ALT	A	691	$2.81	$1,942	34,002 Direct	+2.07%	Acquired	7.5% (price as of 2026-08-20)
March 23, 2023	ALT	P	10,000	$4.22	$42,200	33,311 Direct	+42.90%	Acquired	-28.4% (price as of 2026-08-20)
Feb. 2, 2023	ALT	M	7,775	—	—	23,325 Direct	-25.00%	Disposed	(price as of 2026-08-20)
Feb. 2, 2023	ALT	F	2,364	$15.04	$35,555	23,311 Direct	-9.21%	Disposed	-79.9% (price as of 2026-08-20)
Feb. 2, 2023	ALT	M	7,775	—	—	25,675 Direct	+43.44%	Acquired	(price as of 2026-08-20)
Feb. 1, 2023	ALT	M	6,166	—	—	12,332 Direct	-33.33%	Disposed	(price as of 2026-08-20)
Feb. 1, 2023	ALT	F	2,183	$13.78	$30,082	17,900 Direct	-10.87%	Disposed	-78.1% (price as of 2026-08-20)
Feb. 1, 2023	ALT	M	6,166	—	—	20,083 Direct	+44.31%	Acquired	(price as of 2026-08-20)
Jan. 31, 2023	ALT	A	1,296	$10.21	$13,232	13,917 Direct	+10.27%	Acquired	-70.4% (price as of 2026-08-20)
Jan. 30, 2023	ALT	A	37,100	—	—	37,100 Direct	—	Acquired	(price as of 2026-08-20)
Jan. 30, 2023	ALT	A	105,000	—	—	105,000 Direct	—	Acquired	(price as of 2026-08-20)
July 31, 2022	ALT	A	1,076	$6.86	$7,381	12,621 Direct	+9.32%	Acquired	-56.0% (price as of 2026-08-20)
Feb. 28, 2022	ALT	M	30,000	—	—	31,400 Direct	-48.86%	Disposed	(price as of 2026-08-20)
Feb. 28, 2022	ALT	S 10b5-1	30,000	$7.52	$225,600	11,545 Direct	-72.21%	Disposed	-59.8% (price as of 2026-08-20)
Feb. 28, 2022	ALT	M	30,000	$1.92	$57,600	41,545 Direct	+259.85%	Acquired	57.3% (price as of 2026-08-20)
Feb. 2, 2022	ALT	A	91,600	—	—	91,600 Direct	—	Acquired	(price as of 2026-08-20)
Feb. 2, 2022	ALT	A	31,100	—	—	31,100 Direct	—	Acquired	(price as of 2026-08-20)
Feb. 1, 2022	ALT	M	6,166	—	—	18,498 Direct	-25.00%	Disposed	(price as of 2026-08-20)
Feb. 1, 2022	ALT	M	6,166	—	—	13,728 Direct	+81.54%	Acquired	(price as of 2026-08-20)
Feb. 1, 2022	ALT	F	2,183	$7.98	$17,420	11,545 Direct	-15.90%	Disposed	-62.2% (price as of 2026-08-20)
Jan. 31, 2022	ALT	A	1,800	$6.86	$12,348	7,562 Direct	+31.24%	Acquired	-56.0% (price as of 2026-08-20)
July 31, 2021	ALT	A	725	$7.71	$5,590	5,762 Direct	+14.39%	Acquired	-60.8% (price as of 2026-08-20)
Feb. 1, 2021	ALT	A	24,664	—	—	24,664 Direct	—	Acquired	(price as of 2026-08-20)
Feb. 1, 2021	ALT	A	90,000	—	—	90,000 Direct	—	Acquired	(price as of 2026-08-20)
Jan. 31, 2021	ALT	A	968	$12.14	$11,752	5,037 Direct	+23.79%	Acquired	-75.1% (price as of 2026-08-20)
Nov. 12, 2020	ALT	S 10b5-1	4,015	$10.02	$40,230	4,069 Direct	-49.67%	Disposed	-69.9% (price as of 2026-08-20)
July 31, 2020	ALT	A	8,084	$1.46	$11,803	8,084 Direct	—	Acquired	106.8% (price as of 2026-08-20)
Jan. 2, 2020	ALT	A	61,400	—	—	61,400 Direct	—	Acquired	(price as of 2026-08-20)
Sept. 9, 2019	ALT	A	107,000	—	—	107,000 Direct	—	Acquired	(price as of 2026-08-20)

P = Open-market purchase · S = Sale · A = Grant/award · M = Option exercise · G = Gift · F = Tax withholding

Insider transactions are not a recommendation; sales are often driven by liquidity or tax reasons.

Derivative holdings (Form 4 Table II)

Options, RSUs and convertible securities reported on Form 4 Table II.

Date	Ticker	Security	Underlying	Exercise price	Expiration	Shares	A/D
Feb. 2, 2025	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (7,775)	—	—	7,775	Acquired
Feb. 1, 2025	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (6,166)	—	—	6,166	Acquired
Jan. 30, 2025	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (9,275)	—	—	9,275	Acquired
Jan. 27, 2025	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (63,400)	—	—	63,400	Acquired
Jan. 27, 2025	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (183,600)	$7.00	Jan. 27, 2035	183,600	Acquired
Jan. 25, 2025	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (14,600)	—	—	14,600	Acquired
Feb. 2, 2024	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (7,775)	—	—	7,775	Disposed
Feb. 1, 2024	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (6,166)	—	—	6,166	Disposed
Jan. 30, 2024	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (9,275)	—	—	9,275	Disposed
Jan. 25, 2024	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (58,400)	—	—	58,400	Acquired
Jan. 25, 2024	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (163,200)	$9.28	Jan. 25, 2034	163,200	Acquired
Feb. 2, 2023	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (7,775)	—	—	7,775	Disposed
Feb. 1, 2023	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (6,166)	—	—	6,166	Disposed
Jan. 30, 2023	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (37,100)	—	—	37,100	Acquired
Jan. 30, 2023	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (105,000)	$12.88	Jan. 30, 2033	105,000	Acquired
Feb. 28, 2022	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (30,000)	$1.92	Jan. 2, 2030	30,000	Disposed
Feb. 2, 2022	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (91,600)	$7.53	Feb. 2, 2032	91,600	Acquired
Feb. 2, 2022	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (31,100)	—	—	31,100	Acquired
Feb. 1, 2022	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (6,166)	—	—	6,166	Disposed
Feb. 1, 2021	ALT	Restricted Stock Units	Common Stock, par value $0.0001 (24,664)	—	—	24,664	Acquired
Feb. 1, 2021	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (90,000)	$16.71	Feb. 1, 2031	90,000	Acquired
Jan. 2, 2020	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (61,400)	$1.92	Jan. 2, 2030	61,400	Acquired
Sept. 9, 2019	ALT	Stock Options (option to buy)	Common Stock, par value $0.0001 (107,000)	$2.13	Sept. 9, 2029	107,000	Acquired

Exercise/conversion price is blank when not applicable (e.g. RSUs).

Compensation (DEF 14A)

Matched by name from proxy statements (DEF 14A) — verify against the filing.

ALT

Fiscal year	Salary	Bonus	Stock awards	Option awards	Non-equity incentive	Pension change	Other	Total
2019	$115,032	—	—	—	—	—	$1,233	$287,590

Figures from the Summary Compensation Table of the company's proxy statement (DEF 14A). Compensation is not a recommendation.