ATARA BIOTHERAPEUTICS INC

Ticker: ATRA CUSIP: 046513206 Class: Common Stock

EcoR1 Capital, LLC's Holding History (CIK: 0001587114)

Note: Option positions (PUT/CALL) are excluded.

Q4 2025

Shares 573,183 Value ($000) $10,369 Avg Close $14.93 Range $10.50 - $18.95

Q3 2025

Shares 573,183 Value ($000) $8,214 Avg Close $11.51 Range $7.54 - $14.90

Q2 2025

Shares 573,183 Value ($000) $4,425 Avg Close $7.30 Range $5.00 - $9.68

Q1 2025

Shares 573,183 Value ($000) $3,405 Avg Close $8.73 Range $5.40 - $18.70

Q4 2024

Shares 532,134 Value ($000) $7,083 Avg Close $10.54 Range $7.20 - $14.93

Q3 2024

Shares 468,938 Value ($000) $3,812 Avg Close $8.56 Range $6.50 - $12.98

Q2 2024

Shares 406,679 Value ($000) $3,457 Avg Close $15.04 Range $7.07 - $20.82

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2025	573,183	$10,369	$14.93	$10.50 - $18.95
Q3 2025	573,183	$8,214	$11.51	$7.54 - $14.90
Q2 2025	573,183	$4,425	$7.30	$5.00 - $9.68
Q1 2025	573,183	$3,405	$8.73	$5.40 - $18.70
Q4 2024	532,134	$7,083	$10.54	$7.20 - $14.93
Q3 2024	468,938	$3,812	$8.56	$6.50 - $12.98
Q2 2024	406,679	$3,457	$15.04	$7.07 - $20.82