Atara Biotherapeutics, Inc.

ATRA

Form 4 • Statement of Changes in Beneficial Ownership

SEC Accession Number: 0000905148-26-001143
Filing date: Mar 4, 2026
Earliest execution date: Mar 2, 2026
Reporting Owners: Nguyen AnhCo (CEO)

Summary

Type

Sell

Net shares

-2,996

% of shares

-4.61%

Amount (USD)

$15,237

Insider confidence score

46.3 out of 100

Positive

  • Tax withholding obligation
  • Small sell amount (<$50K)

Negative

  • Large tax withholding sell (≥1% of shares)

Stock transactions

Transaction 1

Security

Common Stock

Action

Sell

Date

2026-03-02

Code

S

Net shares

-198.0

Price per Share

$5.08

Amount (USD)

$1,005.64

Acquired/Disposed

Disposed

Shares Owned Before

64,974.0

Shares Owned After

64,776.0

Transaction 2

Security

Common Stock

Action

Sell

Date

2026-03-02

Code

S

Net shares

-58.0

Price per Share

$5.08

Amount (USD)

$294.64

Acquired/Disposed

Disposed

Shares Owned Before

64,776.0

Shares Owned After

64,718.0

Transaction 3

Security

Common Stock

Action

Sell

Date

2026-03-02

Code

S

Net shares

-1,298.0

Price per Share

$5.09

Amount (USD)

$6,601.63

Acquired/Disposed

Disposed

Shares Owned Before

64,718.0

Shares Owned After

63,420.0

Transaction 4

Security

Common Stock

Action

Sell

Date

2026-03-02

Code

S

Net shares

-1,442.0

Price per Share

$5.09

Amount (USD)

$7,335.45

Acquired/Disposed

Disposed

Shares Owned Before

63,420.0

Shares Owned After

61,978.0

Filing's footnotes

1. Shares sold automatically to satisfy tax withholding obligations in connection with the vesting of previously granted restricted stock units, pursuant to a sale-to-cover provision in the award agreement.

2. The sale price of the reporting person's shares represents the weighted average price of all shares sold by a broker on March 2, 2026 on behalf of a group of employees of the Issuer to satisfy the payment of withholding tax liability of such employees.

This page is for informational purposes only. While we strive for accuracy, the summary may contain inaccuracies or omissions. Please refer to the official SEC filing for authoritative information. Open the SEC filing.