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Alector, Inc.

ALEC
Exchange
Nasdaq
Industry
Biological Products, (No Diagnostic Substances)
SEC CIK
0001653087

In the last 90 days, Alector, Inc. insiders filed 0 open-market purchases and 3 sales; 140 institutions reported holding it in 13F filings for Q2 2026, worth $183.4M in total; no superinvestor holds it.

13F holders, Q3 2025

Institutional positions in Alector, Inc. as of Sep 30, 2025. Investment managers with $100 million or more in US stocks report their long positions on Form 13F within 45 days after each quarter ends. How 13F works

Institutional holders
149
+13 vs. Q2 2025
Shares held
74.7M
+4.24M (+6.0%) vs. Q2 2025
Total value
$221.2M
+$122.5M (+124.1%) vs. Q2 2025
New holders
25
46 more added
Sold out
12
40 more reduced

Compare with Q2 2025: new holders, sold out and not filed yet

Holders and value by quarter

Institutions reporting ALEC on Form 13F each quarter since Q1 2021, and the total value they reported. Values are as of each quarter end, so they also move with the share price.

Institutional holdersQ3 2025: 149 institutions
Q1 2021: 127 institutionsQ2 2021: 138 institutionsQ3 2021: 145 institutionsQ4 2021: 167 institutionsQ1 2022: 166 institutionsQ2 2022: 154 institutionsQ3 2022: 168 institutionsQ4 2022: 155 institutionsQ1 2023: 149 institutionsQ2 2023: 145 institutionsQ3 2023: 149 institutionsQ4 2023: 148 institutionsQ1 2024: 157 institutionsQ2 2024: 160 institutionsQ3 2024: 159 institutionsQ4 2024: 150 institutionsQ1 2025: 141 institutionsQ2 2025: 136 institutionsQ3 2025: 149 institutionsQ4 2025: 131 institutionsQ1 2026: 138 institutionsQ2 2026: 140 institutions
Value heldQ3 2025: $221.2M
Q1 2021: $931.7MQ2 2021: $1.02BQ3 2021: $1.19BQ4 2021: $1.13BQ1 2022: $789.8MQ2 2022: $546.8MQ3 2022: $516.1MQ4 2022: $506.0MQ1 2023: $360.9MQ2 2023: $354.5MQ3 2023: $402.6MQ4 2023: $510.1MQ1 2024: $446.6MQ2 2024: $330.4MQ3 2024: $338.4MQ4 2024: $138.8MQ1 2025: $89.1MQ2 2025: $98.7MQ3 2025: $221.2MQ4 2025: $131.5MQ1 2026: $190.0MQ2 2026: $183.4M
Institutions holding ALEC and their total value by quarter
QuarterHoldersValue
Q2 2026140$183.4M
Q1 2026138$190.0M
Q4 2025131$131.5M
Q3 2025149$221.2M
Q2 2025136$98.7M
Q1 2025141$89.1M
Q4 2024150$138.8M
Q3 2024159$338.4M
Q2 2024160$330.4M
Q1 2024157$446.6M
Q4 2023148$510.1M
Q3 2023149$402.6M
Q2 2023145$354.5M
Q1 2023149$360.9M
Q4 2022155$506.0M
Q3 2022168$516.1M
Q2 2022154$546.8M
Q1 2022166$789.8M
Q4 2021167$1.13B
Q3 2021145$1.19B
Q2 2021138$1.02B
Q1 2021127$931.7M

Institutions, Q3 2025

Shares, value and share of portfolio for each institution holding Alector, Inc.; share changes are against Q2 2025.

Institutions holding ALEC in Q3 2025
InstitutionSharesValue% of portfolioChange in sharesAction
Marshall Wace, LLP151,643$448.9K0.00%+151,643New
Alphabet Inc.175,866$520.6K0.02%00.0%Unchanged
Invesco Ltd.192,311$569.2K0.00%+16,510+9.4%Added
Manufacturers Life Insurance Company, The216,574$641.1K0.00%−97,004−30.9%Reduced
Bank of New York Mellon Corp224,484$664.5K0.00%−44,388−16.5%Reduced
UBS Group AG230,499$682.3K0.00%+188,606+450.2%Added
Bank of America Corp246,283$729.0K0.00%−97,626−28.4%Reduced
TD Asset Management Inc273,738$810.3K0.00%−378,000−58.0%Reduced
Ameriprise Financial Inc274,042$811.2K0.00%+259,907+1,838.7%Added
Mackenzie Financial Corp283,712$839.8K0.00%+9,270+3.4%Added
Dimensional Fund Advisors LP295,846$876.0K0.00%−87,485−22.8%Reduced
Two Sigma Investments, LP307,179$909.3K0.00%+85,040+38.3%Added
Susquehanna International Group, LLP308,660$913.6K0.00%+104,862+51.5%Added
New Leaf Venture Partners, L.L.C.339,569$1.01M2.33%00.0%Unchanged
Jane Street Group, LLC350,231$1.04M0.00%+326,279+1,362.2%Added
Morgan Stanley434,168$1.29M0.00%−172,384−28.4%Reduced
AQR Capital Management LLC438,087$1.30M0.00%+31,469+7.7%Added
Citadel Advisors LLC471,581$1.40M0.00%−80,239−14.5%Reduced
Medici Capital LLC481,974$1.43M1.06%+314,783+188.3%Added
Two Sigma Advisers, LP517,400$1.53M0.00%+140,400+37.2%Added
Boothbay Fund Management, LLC524,077$1.55M0.04%+65,214+14.2%Added
Goldman Sachs Group Inc609,909$1.81M0.00%+235,432+62.9%Added
Royal Bank of Canada628,652$1.86M0.00%+261,464+71.2%Added
Northern Trust Corp633,709$1.88M0.00%−24,452−3.7%Reduced
Charles Schwab Investment Management Inc689,524$2.04M0.00%+41,871+6.5%Added
Panagora Asset Management Inc741,293$2.19M0.01%+224,613+43.5%Added
Ikarian Capital, LLC760,000$2.25M0.51%−140,000−15.6%Reduced
DAFNA Capital Management LLC798,351$2.36M0.58%−114,577−12.6%Reduced
Barclays PLC873,375$2.59M0.00%+703,580+414.4%Added
Renaissance Technologies LLC949,150$2.81M0.00%−305,700−24.4%Reduced
D. E. Shaw & Co., Inc.978,204$2.90M0.00%+444,004+83.1%Added
Vestal Point Capital, LP980,000$2.90M0.13%+3,008+0.3%Added
5AM Venture Management, LLC995,841$2.95M1.08%00.0%Unchanged
683 Capital Management, LLC1,000,000$2.96M0.27%+1,000,000New
Deerfield Management Company, L.P. (Series C)1,055,192$3.12M0.05%00.0%Unchanged
Deutsche Bank AG1,068,215$3.16M0.00%+78,468+7.9%Added
Millennium Management LLC1,155,027$3.42M0.00%+744,224+181.2%Added
Jacobs Levy Equity Management, Inc1,230,974$3.64M0.01%−91,908−6.9%Reduced
Euclidean Capital LLC1,307,858$3.87M1.63%00.0%Unchanged
Eversept Partners, LP1,488,725$4.41M0.34%−497,347−25.0%Reduced
State Street Corp1,734,679$5.13M0.00%+24,777+1.4%Added
Geode Capital Management, LLC1,861,258$5.51M0.00%−120,810−6.1%Reduced
Price T Rowe Associates Inc2,185,032$6.47M0.00%−2,690,232−55.2%Reduced
Acadian Asset Management LLC2,372,985$7.02M0.01%+202,597+9.3%Added
Merck & Co., Inc.3,545,719$10.5M4.60%00.0%Unchanged
Vanguard Group Inc6,034,659$17.9M0.00%+46,955+0.8%Added
RTW Investments, LP6,990,806$20.7M0.25%+6,990,806New
BlackRock, Inc.7,197,973$21.3M0.00%−775,607−9.7%Reduced
FMR LLC15,181,849$44.9M0.00%+182,960+1.2%Added
ADAR1 Capital Management, LLC0$00.00%−1,723,526−100.0%Sold out
Sio Capital Management, LLC0$00.00%−845,531−100.0%Sold out
Walleye Capital LLC0$00.00%−266,204−100.0%Sold out
State of Wyoming0$00.00%−223,092−100.0%Sold out
Gsa Capital Partners LLP0$00.00%−150,669−100.0%Sold out
Susquehanna Fundamental Investments, LLC0$00.00%−70,778−100.0%Sold out
Algert Global LLC0$00.00%−44,460−100.0%Sold out
State Board of Administration of Florida Retirement System0$00.00%−25,570−100.0%Sold out
Shell Asset Management Co0$00.00%−13,887−100.0%Sold out
US Bancorp0$00.00%−12,427−100.0%Sold out
Raymond James Financial Inc0$00.00%−1,479−100.0%Sold out
Skopos Labs, Inc.0$00.00%−601−100.0%Sold out