Joseph C. Breunig

Insider

First SEC filing: Nov. 12, 2014 · Latest: May 21, 2026

On this page

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.
Initial holdings The stakes this person held when they first started reporting.

Insider at

MTX buying Feb. 7, 2018

Insider transactions

0 buys (P) 0 sells (S) Net: $0 + 35 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

35 other filings hidden

Date	Ticker	Code	Shares	Price	Value	Owned after	Δ own	A/D	vs now
June 18, 2026	MTX	A	33	—	—	21,563 Direct	+0.15%	Acquired	(price as of 2026-08-20)
May 20, 2026	MTX	A	1,908	—	—	21,531 Direct	+9.72%	Acquired	(price as of 2026-08-20)
March 6, 2026	MTX	A	35	—	—	19,622 Direct	+0.18%	Acquired	(price as of 2026-08-20)
Dec. 4, 2025	MTX	A	40	—	—	19,588 Direct	+0.20%	Acquired	(price as of 2026-08-20)
Sept. 5, 2025	MTX	A	33	—	—	19,548 Direct	+0.17%	Acquired	(price as of 2026-08-20)
June 12, 2025	MTX	A	38	—	—	19,514 Direct	+0.20%	Acquired	(price as of 2026-08-20)
May 14, 2025	MTX	A	2,500	—	—	19,476 Direct	+14.73%	Acquired	(price as of 2026-08-20)
March 7, 2025	MTX	A	27	—	—	16,976 Direct	+0.16%	Acquired	(price as of 2026-08-20)
Dec. 5, 2024	MTX	A	23	—	—	16,948 Direct	+0.14%	Acquired	(price as of 2026-08-20)
Sept. 6, 2024	MTX	A	24	—	—	16,925 Direct	+0.14%	Acquired	(price as of 2026-08-20)
June 13, 2024	MTX	A	20	—	—	16,902 Direct	+0.12%	Acquired	(price as of 2026-08-20)
May 15, 2024	MTX	A	1,542	—	—	16,881 Direct	+10.05%	Acquired	(price as of 2026-08-20)
March 7, 2024	MTX	A	21	—	—	15,340 Direct	+0.14%	Acquired	(price as of 2026-08-20)
Dec. 7, 2023	MTX	A	24	—	—	15,319 Direct	+0.16%	Acquired	(price as of 2026-08-20)
Sept. 8, 2023	MTX	A	14	—	—	15,295 Direct	+0.09%	Acquired	(price as of 2026-08-20)
June 15, 2023	MTX	A	14	—	—	15,281 Direct	+0.09%	Acquired	(price as of 2026-08-20)
May 17, 2023	MTX	A	2,067	—	—	15,267 Direct	+15.66%	Acquired	(price as of 2026-08-20)
June 14, 2018	MTX	A	4	—	—	5,462 Direct	+0.07%	Acquired	(price as of 2026-08-20)
May 16, 2018	MTX	A	1,381	—	—	5,459 Direct	+33.86%	Acquired	(price as of 2026-08-20)
May 16, 2018	MTX	A	1,344	—	—	5,422 Direct	+32.96%	Acquired	(price as of 2026-08-20)
March 8, 2018	MTX	A	3	—	—	4,077 Direct	+0.07%	Acquired	(price as of 2026-08-20)
Feb. 7, 2018	MTX	P	800	$69.36	$55,488	1,200 Direct	+200.00%	Acquired	1.9% (price as of 2026-08-20)
Dec. 8, 2017	MTX	A	3	—	—	4,075 Direct	+0.07%	Acquired	(price as of 2026-08-20)
Sept. 7, 2017	MTX	A	3	—	—	4,072 Direct	+0.07%	Acquired	(price as of 2026-08-20)
June 9, 2017	MTX	A	3	—	—	4,068 Direct	+0.07%	Acquired	(price as of 2026-08-20)
May 17, 2017	MTX	A	1,381	—	—	4,066 Direct	+51.43%	Acquired	(price as of 2026-08-20)
March 9, 2017	MTX	A	2	—	—	2,685 Direct	+0.07%	Acquired	(price as of 2026-08-20)
Dec. 9, 2016	MTX	A	2	—	—	2,683 Direct	+0.07%	Acquired	(price as of 2026-08-20)
Sept. 8, 2016	MTX	A	2	—	—	2,681 Direct	+0.07%	Acquired	(price as of 2026-08-20)
June 9, 2016	MTX	A	2	—	—	2,679 Direct	+0.07%	Acquired	(price as of 2026-08-20)
May 11, 2016	MTX	A	1,496	—	—	2,677 Direct	+126.67%	Acquired	(price as of 2026-08-20)
March 10, 2016	MTX	A	1	—	—	1,181 Direct	+0.08%	Acquired	(price as of 2026-08-20)
Dec. 10, 2015	MTX	A	1	—	—	1,180 Direct	+0.08%	Acquired	(price as of 2026-08-20)
Sept. 10, 2015	MTX	A	1	—	—	1,179 Direct	+0.08%	Acquired	(price as of 2026-08-20)
June 10, 2015	MTX	A	1	—	—	1,178 Direct	+0.08%	Acquired	(price as of 2026-08-20)
May 13, 2015	MTX	A	1,177	—	—	1,177 Direct	—	Acquired	(price as of 2026-08-20)
March 19, 2015	MTX	P	400	$69.83	$27,932	400 Direct	—	Acquired	1.2% (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
June 18, 2026	MTX	PHANTOM STOCK UNITS	COMMON STOCK (33)	—	—	33	Acquired
May 20, 2026	MTX	PHANTOM STOCK UNITS	COMMON STOCK (1,908)	—	—	1,908	Acquired
March 6, 2026	MTX	PHANTOM STOCK UNITS	COMMON STOCK (35)	—	—	35	Acquired
Dec. 4, 2025	MTX	PHANTOM STOCK UNITS	COMMON STOCK (40)	—	—	40	Acquired
Sept. 5, 2025	MTX	PHANTOM STOCK UNITS	COMMON STOCK (33)	—	—	33	Acquired
June 12, 2025	MTX	PHANTOM STOCK UNITS	COMMON STOCK (38)	—	—	38	Acquired
May 14, 2025	MTX	PHANTOM STOCK UNITS	COMMON STOCK (2,500)	—	—	2,500	Acquired
March 7, 2025	MTX	PHANTOM STOCK UNITS	COMMON STOCK (27)	—	—	27	Acquired
Dec. 5, 2024	MTX	PHANTOM STOCK UNITS	COMMON STOCK (23)	—	—	23	Acquired
Sept. 6, 2024	MTX	PHANTOM STOCK UNITS	COMMON STOCK (24)	—	—	24	Acquired
June 13, 2024	MTX	PHANTOM STOCK UNITS	COMMON STOCK (20)	—	—	20	Acquired
May 15, 2024	MTX	PHANTOM STOCK UNITS	COMMON STOCK (1,542)	—	—	1,542	Acquired
March 7, 2024	MTX	PHANTOM STOCK UNITS	COMMON STOCK (21)	—	—	21	Acquired
Dec. 7, 2023	MTX	PHANTOM STOCK UNITS	COMMON STOCK (24)	—	—	24	Acquired
Sept. 8, 2023	MTX	PHANTOM STOCK UNITS	COMMON STOCK (14)	—	—	14	Acquired
June 15, 2023	MTX	PHANTOM STOCK UNITS	COMMON STOCK (14)	—	—	14	Acquired
May 17, 2023	MTX	PHANTOM STOCK UNITS	COMMON STOCK (2,067)	—	—	2,067	Acquired
June 14, 2018	MTX	Phantom Stock Units	Common Stock (4)	—	—	4	Acquired
May 16, 2018	MTX	Phantom Stock Units	Common Stock	—	—	1,381	Acquired
May 16, 2018	MTX	Phantom Stock Units	Common Stock (1,344)	—	—	1,344	Acquired
March 8, 2018	MTX	Phantom Stock Units	Common Stock (3)	—	—	3	Acquired
Dec. 8, 2017	MTX	Phantom Stock Units	Common Stock (3)	—	—	3	Acquired
Sept. 7, 2017	MTX	Phantom Stock Units	Common Stock (3)	—	—	3	Acquired
June 9, 2017	MTX	Phantom Stock Units	Common Stock (3)	—	—	3	Acquired
May 17, 2017	MTX	Phantom Stock Units	Common Stock (1,381)	—	—	1,381	Acquired
March 9, 2017	MTX	Phantom Stock Units	Common Stock (2)	—	—	2	Acquired
Dec. 9, 2016	MTX	Phantom Stock Units	Common Stock (2)	—	—	2	Acquired
Sept. 8, 2016	MTX	Phantom Stock Units	Common Stock (2)	—	—	2	Acquired
June 9, 2016	MTX	Phantom Stock Units	Common Stock (2)	—	—	2	Acquired
May 11, 2016	MTX	Phantom Stock Units	Common Stock (1,496)	—	—	1,496	Acquired
March 10, 2016	MTX	Phantom Stock Units	Common Stock (1)	—	—	1	Acquired
Dec. 10, 2015	MTX	Phantom Stock Units	Common Stock (1)	—	—	1	Acquired
Sept. 10, 2015	MTX	Phantom Stock Units	Common Stock (1)	—	—	1	Acquired
June 10, 2015	MTX	Phantom Stock Units	Common Stock (1)	—	—	1	Acquired
May 13, 2015	MTX	Phantom Stock Units	Common Stock (1,177)	—	—	1,177	Acquired

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

Initial ownership (Form 3) 1 holding

Securities held when first becoming an insider, per SEC Form 3.

Date	Ticker	Security	Shares	Ownership
Nov. 12, 2014	MTX	Common Stock	0	Direct