Alector, Inc.
US ˙ NasdaqGS ˙ US0144421072

SecurityALEC / Alector, Inc.
InstitutionState Street Corp
Latest Disclosed Ownership1,865,526 shares
Latest Disclosed Value $ 4,010,881
State Street Corp reports 2.82% increase in ownership of ALEC / Alector, Inc.

On May 15, 2026 - State Street Corp filed a 13F-HR form disclosing ownership of 1,865,526 shares of Alector, Inc. (US:ALEC) valued at $4,010,881 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 1,814,298 shares of Alector, Inc.. This represents a change in shares of 2.82% during the quarter. The current value of the position is $3,376,602 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F ALECTOR COM 014442107 1,865,526 51,228 2.82 4,011 41.70 0.0001
2026-02-13 2025-12-31 13F ALECTOR COM 014442107 1,814,298 79,619 4.59 2,830 -44.88 0.0001
2025-11-14 2025-09-30 13F ALECTOR COM 014442107 1,734,679 24,777 1.45 5,135 114.54 0.0002
2025-08-14 2025-06-30 13F ALECTOR COM 014442107 1,709,902 69,640 4.25 2,394 18.64 0.0001
2025-05-15 2025-03-31 13F ALECTOR COM 014442107 1,640,262 -209,033 -11.30 2,018 -42.29 0.0001
2025-02-14 2024-12-31 13F ALECTOR COM 014442107 1,849,295 -767,514 -29.33 3,495 -71.34 0.0001
2024-11-14 2024-09-30 13F ALECTOR COM 014442107 2,616,809 -173,068 -6.20 12,194 -3.73 0.0005
2024-08-14 2024-06-30 13F ALECTOR COM 014442107 2,789,877 -1,125,292 -28.74 12,666 -46.26 0.0006
2024-05-15 2024-03-31 13F ALECTOR COM 014442107 3,915,169 797,640 25.59 23,569 -5.26 0.0011
2024-02-14 2023-12-31 13F ALECTOR COM 014442107 3,117,529 280,822 9.90 24,878 35.34 0.0012
2023-11-14 2023-09-30 13F ALECTOR COM 014442107 2,836,707 117,560 4.32 18,382 12.48 0.0010
2023-08-14 2023-06-30 13F ALECTOR COM 014442107 2,719,147 -846,184 -23.73 16,342 -25.95 0.0009
2023-05-15 2023-03-31 13F ALECTOR COM 014442107 3,565,331 335,814 10.40 22,069 -25.96 0.0012
2023-05-15 2022-12-31 13F/A-99 ALECTOR COM 014442107 3,229,517 -64,080 -1.95 29,808 -4.33 0.0018
2023-05-15 2022-12-31 13F ALECTOR COM 014442107 3,229,517 -64,080 29,808 0.0018
2022-11-15 2022-09-30 13F ALECTOR COM 014442107 3,293,597 -620,739 -15.86 31,157 -21.66 0.0020
2022-08-15 2022-06-30 13F ALECTOR COM 014442107 3,914,336 78,243 2.04 39,770 -27.25 0.0024
2022-05-16 2022-03-31 13F ALECTOR COM 014442107 3,836,093 772,398 25.21 54,664 -13.60 0.0027
2022-02-14 2021-12-31 13F ALECTOR COM 014442107 3,063,695 -520,824 -14.53 63,265 -22.66 0.0030
2021-11-15 2021-09-30 13F ALECTOR COM 014442107 3,584,519 843,189 30.76 81,799 43.25 0.0043
2021-08-16 2021-06-30 13F ALECTOR COM 014442107 2,741,330 28,234 1.04 57,102 4.50 0.0030
2021-07-09 2021-03-31 13F/A-1 ALECTOR COM 014442107 2,713,096 -338,435 -11.09 54,642 18.35 0.0031
2021-05-17 2021-03-31 13F ALECTOR COM 014442107 2,713,096 -338,435 54,642 0.0031
2021-02-16 2020-12-31 13F ALECTOR COM 014442107 3,051,531 -534,865 -14.91 46,170 22.20 0.0028
2020-11-10 2020-09-30 13F ALECTOR COM 014442107 3,586,396 1,776,001 98.10 37,783 -14.61 0.0026
2020-08-14 2020-06-30 13F ALECTOR COM 014442107 1,810,395 676,606 59.68 44,246 61.73 0.0032
2020-06-19 2020-03-31 13F/A-1 ALECTOR COM 014442107 1,133,789 93,046 8.94 27,358 52.57 0.0024
2020-05-11 2020-03-31 13F ALECTOR COM 014442107 1,133,789 93,046 27,358 2,402.5833
2020-02-06 2019-12-31 13F ALECTOR COM 014442107 1,040,743 562,076 117.43 17,932 159.81 0.0012
2019-11-14 2019-09-30 13F ALECTOR COM 014442107 478,667 331,642 225.57 6,902 147.12 0.0005
2019-08-14 2019-06-30 13F ALECTOR COM 014442107 147,025 64,081 77.26 2,793 79.85 0.0002
2019-05-15 2019-03-31 13F ALECTOR COM 014442107 82,944 82,944 1,553 0.0001
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.