MasTec (NYSE: MTZ) director reports stock grant and tax-withholding share disposition

Rhea-AI Filing Summary

MASTEC INC director Ernst N. Csiszar reported routine equity compensation activity. He received a grant of 104 shares of common stock, recorded at a zero dollar purchase price as an award. On the same date, 23 shares were disposed of to cover taxes due upon vesting of restricted stock. Following these transactions, he directly holds 17,339 shares of MasTec common stock.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Csiszar Ernst N

Role null

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	104	$0.00	--
Tax Withholding	Common Stock	23	$434.77	$10K

Holdings After Transaction: Common Stock — 17,339 shares (Direct, null)

Footnotes (1)

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Key Figures

Shares granted: 104 shares Tax-withheld shares: 23 shares Holding after grant: 17,339 shares +1 more

4 metrics

Shares granted 104 shares Equity grant coded as acquisition (A) on May 15, 2026

Tax-withheld shares 23 shares Withheld to pay taxes on restricted stock vesting

Holding after grant 17,339 shares Total MasTec common shares directly held after transactions

Implied price for tax shares $434.77 per share Value used for 23 tax-withheld shares

Key Terms

restricted stock, tax-withholding disposition, grant/award acquisition, Form 4

4 terms

restricted stock financial

"taxes due upon vesting of restricted stock"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

tax-withholding disposition financial

"transaction_action: tax-withholding disposition"

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

grant/award acquisition financial

"transaction_action: grant/award acquisition"

Form 4 regulatory

"INSIDER FILING DATA (Form 4)"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Csiszar Ernst N

(Last) (First) (Middle)

1579 KATHWOOD DR.

(Street)

COLUMBIA SOUTH CAROLINA 29206

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
MASTEC INC [ MTZ ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/15/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/15/2026		A		104	A	$0	17,339	D
Common Stock	05/15/2026		F		23(1)	D	$434.77	17,316	D

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Shares disposed of represent shares withheld by the Issuer to pay taxes due upon vesting of restricted stock.

Remarks:

	\s\ Alberto de Cardenas For: Ernst Csiszar	05/19/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transactions did MasTec (MTZ) director Ernst N. Csiszar report?

Ernst N. Csiszar reported a grant of 104 MasTec common shares and a tax-withholding disposition of 23 shares tied to restricted stock vesting. These non-market transactions are routine equity compensation events rather than open-market buying or selling.

Did Ernst N. Csiszar buy or sell MasTec (MTZ) stock on the open market?

The filing shows no open-market buys or sells. It reports a share grant and 23 shares withheld to pay taxes on restricted stock vesting, which are compensation and tax events, not discretionary trading in MasTec stock.

How many MasTec (MTZ) shares does Ernst N. Csiszar hold after this Form 4?

After the reported transactions, Ernst N. Csiszar directly holds 17,339 shares of MasTec common stock. This reflects the net result of receiving 104 granted shares and 23 shares withheld by the company for tax obligations on restricted stock vesting.

What does the tax-withholding disposition mean in the MasTec (MTZ) Form 4?

The tax-withholding disposition of 23 shares means MasTec retained that number of shares to cover taxes due when restricted stock vested. This is not an open-market sale but an automatic method of paying tax liabilities in shares instead of cash.

What is the significance of the A and F transaction codes in the MasTec (MTZ) filing?

Code A reflects a grant or award acquisition of 104 common shares, while code F reflects 23 shares withheld to pay tax liabilities on restricted stock vesting. Both are standard equity compensation mechanisms and do not represent open-market trading activity.