SIRIOS CAPITAL MANAGEMENT L P ANNX β€” ANNEXON INC

Ownership history in SIRIOS CAPITAL MANAGEMENT L P  Β·  4 quarters on record

AI Ownership Summary

SIRIOS CAPITAL MANAGEMENT L P reported ANNEXON INC (ANNX) in 4 quarterly 13F filings from 2025 Q1 through 2025 Q4. Peak portfolio weight reached 0.44% in 2025 Q4. The latest visible filing shows ANNX at 0.44% of the fund.

This page tracks quarterly shares, estimated market value, portfolio weight, filing dates, and disclosure-aligned stock prices directly from SEC EDGAR 13F filings.

What this ANNX ownership page tells you

This page is designed to answer the real investor question behind a 13F filing: how meaningful was SIRIOS CAPITAL MANAGEMENT L P's position in ANNEXON INC, and how did that conviction change over time? You can read the holding window, peak weight, latest reported size, disclosure timing, and quarter-by-quarter changes without piecing the story together from raw SEC rows.

Freshest filing
Latest Reported Filing
2025 Q4

ANNX was reported at 0.44% of portfolio in the most recent visible filing.

High-water mark
Peak Conviction
0.44% in 2025 Q4

Peak weight helps separate a token disclosure from a real conviction holding the fund genuinely cared about.

Time in book
Holding Window
2025 Q1 to 2025 Q4

Longer holding windows often tell a very different story from short-lived tactical trades or one-quarter experiments.

Decision context
Why It Matters
Position size beats headlines

Knowing that a fund owned a stock is useful. Knowing whether it was a 0.20% placeholder or a true high-conviction position is where the signal actually starts.

ANNX stock page SIRIOS CAPITAL MANAGEMENT L P fund profile SIRIOS CAPITAL MANAGEMENT L P full holdings
How SIRIOS CAPITAL MANAGEMENT L P held ANNX β€” position size vs. price
% of Fund (quarterly)    ANNX price (quarter-end, indexed to 100)    SPY (indexed to 100)    QQQ (indexed to 100)
πŸ“‹ Quarterly Holdings History 4 quarters  β–Ύ
Quarter Action Sold % After 3M Timing Shares Change Chg % % of Fund Mkt Value Filed Price (Filed)
2025 Q4 REDUCED 26.8% +10.4% ❌ 710,256 -259,944 -26.8% 0.44% $3.6M 2026-02-14 (Est.) $4.89
2025 Q3 REDUCED β€” β€” β€” 970,200 -19,377 -2.0% 0.39% $3.0M 2025-11-14 $2.71
2025 Q2 ADDED β€” β€” β€” 989,577 +220,891 +28.7% 0.34% $2.4M 2025-08-14 $2.38
2025 Q1 INITIATED β€” β€” β€” 768,686 β€” β€” 0.26% $1.5M 2025-05-15 $1.81

🏒 Other funds also holding ANNX

As of 2026 Q1 β€” sorted by position size

Board of Trustees of The Leland Stanford Junior University 3Y 7Y 0.31% Y-Intercept (Hong Kong) Ltd 3Y 0.14% AlphaCentric Advisors LLC 3Y 0.14% MOUNT VERNON ASSOCIATES INC /MD/ 3Y 7Y 0.04% Allegheny Financial Group 3Y 0.03% MUTUAL OF AMERICA CAPITAL MANAGEMENT LLC 3Y 7Y 0.03% China Universal Asset Management Co., Ltd. 3Y 0.02% PROFUND ADVISORS LLC 3Y 7Y 0.02% Balefire, LLC 3Y 7Y 0.02% Abel Hall, LLC 0.01%

FAQ About SIRIOS CAPITAL MANAGEMENT L P and ANNX

These are the practical questions this page is built to answer before you even open the full history table.

How long has SIRIOS CAPITAL MANAGEMENT L P reported owning ANNX?

SIRIOS CAPITAL MANAGEMENT L P reported ANNX across 4 quarterly 13F filings, from 2025 Q1 through 2025 Q4.

What was the largest reported ANNX position in SIRIOS CAPITAL MANAGEMENT L P's portfolio?

The largest reported portfolio weight for ANNX was 0.44% in 2025 Q4.

What is the latest reported ANNX position on this page?

The most recent filing on this page is 2025 Q4, when SIRIOS CAPITAL MANAGEMENT L P reported 710,256 shares, equal to 0.44% of portfolio, with an estimated market value of $3.6M.

What does the chart on this ANNX ownership page compare?

The chart compares SIRIOS CAPITAL MANAGEMENT L P's quarterly ANNX portfolio weight with the stock's indexed share price, so you can see whether the fund was building, trimming, or holding the position as price moved.

How well did SIRIOS CAPITAL MANAGEMENT L P time their ANNX position?

Based on 13F filing dates vs. subsequent ANNX price moves, SIRIOS CAPITAL MANAGEMENT L P correctly timed 2 out of 3 reported position changes (67%).

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