MTX (NYSE: MTX) insider files Rule 144 to sell 23,093 shares

Rhea-AI Filing Summary

An MTX insider filed a notice to sell 23,093 common shares under Rule 144. The shares are to be sold through Fidelity Brokerage Services LLC on the NYSE, with an aggregate market value of $1,429,523.71. The filing notes that 31,134,308 shares of this class were outstanding at the time of the notice, giving context to the size of the planned sale.

The seller acquired the 23,093 shares on 12/29/2025 by exercising a stock option that had originally been granted on 01/19/2016, paying the exercise price in cash. By signing the notice, the seller represents that they are not aware of any undisclosed material adverse information about MTX’s current or prospective operations.

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK
Filer CCC
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.

Relationship to Issuer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	23093	1429523.71	31134308	12/29/2025	NYSE

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	12/29/2025	Option Granted 01/19/2016	Issuer			23093	12/29/2025	Cash

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Nothing to Report

144: Remarks and Signature

Remarks

Date of Notice

ATTENTION:

The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.

Signature

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does the MTX Rule 144 filing disclose?

It discloses that an MTX insider plans to sell 23,093 common shares on the NYSE under Rule 144, with an aggregate market value of $1,429,523.71.

How many MTX shares are being sold and what is their market value?

The filing states that 23,093 common shares are to be sold, with an aggregate market value of $1,429,523.71.

When and how did the insider acquire the MTX shares being sold?

The insider acquired the 23,093 common shares on 12/29/2025 by exercising a stock option granted on 01/19/2016, paying the exercise price in cash.

On which exchange will the MTX shares be sold and through which broker?

The shares are expected to be sold on the NYSE through Fidelity Brokerage Services LLC, located in Smithfield, RI.

How does this MTX insider sale compare to total shares outstanding?

The filing reports that 31,134,308 common shares were outstanding, providing context for the planned sale of 23,093 shares.

What representation does the MTX insider make in the Rule 144 notice?

By signing, the insider represents that they do not know of any material adverse information about MTX’s current or prospective operations that has not been publicly disclosed.