Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Rust Scott Arthur
  2. Issuer Name and Ticker or Trading Symbol
NATIONAL INSTRUMENTS CORP [NATI]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Senior Vice President
(Last)
(First)
(Middle)
C/O NATIONAL INSTRUMENTS CORPORATION, 11500 NORTH MOPAC
3. Date of Earliest Transaction (Month/Day/Year)
02/01/2019
(Street)

AUSTIN, TX 78759
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
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 02/01/2019   M V 199 (1) A $ 37.587 36,274 D  
Common Stock 05/01/2019   M V 154 (1) A $ 37.587 36,428 D  
Common Stock 05/01/2019   M   11,326 A (2) 47,754 D  
Common Stock 05/01/2019   F   4,068 D $ 43.4716 43,686 D  

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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 Underlying Securities
(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 of Derivative Security: 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
Restricted Stock Units (2) 05/01/2019   M     851   (3) 05/01/2026 Common Stock 851 $ 0 808 D  
Restricted Stock Units (2) 05/01/2019   M     794   (3) 05/01/2027 Common Stock 794 $ 0 1,715 D  
Restricted Stock Units (2) 05/01/2019   M     510   (3) 05/01/2028 Common Stock 510 $ 0 1,625 D  
Restricted Stock Units (2) 05/01/2019   M     567   (3) 05/01/2029 Common Stock 567 $ 0 2,316 D  
Restricted Stock Units (2) 05/01/2019   M     1,701   (3) 05/01/2030 Common Stock 1,701 $ 0 8,639 D  
Restricted Stock Units (2) 05/01/2019   M     1,903   (3) 05/01/2031 Common Stock 1,903 $ 0 9,776 D  
Restricted Stock Units (2) 05/01/2019   M     5,000   (4) 05/01/2032 Common Stock 5,000 $ 0 10,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Rust Scott Arthur
C/O NATIONAL INSTRUMENTS CORPORATION
11500 NORTH MOPAC
AUSTIN, TX 78759
      Senior Vice President  

Signatures

 R. Eddie Dixon, Jr. as attorney-in-fact for Scott Arthur Rust   05/02/2019
**Signature of Reporting Person Date

Explanation of Responses:

* 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).
(1) Acquisition of stock under Issuer's employee stock purchase plan.
(2) Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock.
(3) The restricted stock units vest and become exercisable based on time and performance milestones set by the Issuer.
(4) The restricted stock units vest in four equal annual installments on the anniversary of the vesting commencement date of May 1, 2017.

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