EC
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EcoR1 Capital’s Atara Biotherapeutics ATRA Stock Holding History

EcoR1 Capital’s Portfolio ATRA Stock Details ATRA Fund Activity
Bought
Maintained
Sold
Quarter Market Value Status Shares Change in
Stake 		Trade Value Portfolio Weight Portfolio Position
2026
Q1 		$471K Sell
99,593
-473,590
-83% -$2.89M 0.02% 29
2025
Q4 		$10.4M Hold
573,183
– – 0.47% 22
2025
Q3 		$8.21M Hold
573,183
– – 0.39% 24
2025
Q2 		$4.42M Hold
573,183
– – 0.26% 32
2025
Q1 		$3.4M Buy
573,183
+41,049
+8% +$358K 0.2% 33
2024
Q4 		$7.08M Buy
532,134
+63,196
+13% +$666K 0.27% 41
2024
Q3 		$3.81M Buy
468,938
+62,259
+15% +$533K 0.13% 49
2024
Q2 		$3.46M Sell
406,679
-3
-0% -$45 0.11% 48
2024
Q1 		$7.06M Buy
406,682
+4,000
+1% +$71K 0.18% 48
2023
Q4 		$5.16M Buy
+402,682
New +$9.39M 0.13% 38
2017
Q2 		– Sell
-17,392
Closed -$8.94M – 37
2017
Q1 		$8.94M Buy
17,392
+8,760
+101% +$3.63M 2.26% 12
2016
Q4 		$3.06M Buy
+8,632
New +$3.65M 0.98% 17
2015
Q4 		– Sell
-32,138
Closed -$25.3M – 32
2015
Q3 		$25.3M Sell
32,138
-10,390
-24% -$12.7M 11.5% 2
2015
Q2 		$56.1M Hold
42,528
– – 18.7% 1
2015
Q1 		$44.2M Buy
42,528
+27,123
+176% +$17.9M 14.73% 1
2014
Q4 		$10.1M Buy
+15,405
New +$9.41M 5.13% 8

Other funds holding ATRA

Adage Capital Partners
Adage Capital Partners Boston, Massachusetts $64.8B AUM 42.7% 1-Year Est. Return
RG
Redmile Group San Francisco, California $1.51B AUM 164.17% 1-Year Est. Return
Mackenzie Financial
Mackenzie Financial Toronto Ontario, Ontario, Canada $83.3B AUM 31.19% 1-Year Est. Return
VCM
Vanguard Capital Management Malvern, Pennsylvania $4.04T AUM
Point72 Asset Management
Point72 Asset Management Stamford, Connecticut $78.1B AUM 55.25% 1-Year Est. Return
Acadian Asset Management
Acadian Asset Management Boston, Massachusetts $70.5B AUM 36% 1-Year Est. Return
BlackRock
BlackRock New York $5.72T AUM 30.48% 1-Year Est. Return
Geode Capital Management
Geode Capital Management Boston, Massachusetts $1.61T AUM 30.72% 1-Year Est. Return
UBS Group
UBS Group Zurich, Switzerland $666B AUM 30.12% 1-Year Est. Return
SCA
STALEY CAPITAL ADVISERS Pittsburgh, Pennsylvania $2.36B AUM 23.72% 1-Year Est. Return