ARDSLEY ADVISORY PARTNERS LP MGNI — MAGNITE INC

Ownership history in ARDSLEY ADVISORY PARTNERS LP  ·  12 quarters on record

AI Ownership Summary

ARDSLEY ADVISORY PARTNERS LP reported MAGNITE INC (MGNI) in 12 quarterly 13F filings from 2024 Q1 through 2025 Q3. Peak portfolio weight reached 1.17% in 2025 Q2. The latest visible filing shows MGNI at 0.53% 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. Older history is available after unlock; the visible window still shows the most recent pattern.

What this MGNI ownership page tells you

This page is designed to answer the real investor question behind a 13F filing: how meaningful was ARDSLEY ADVISORY PARTNERS LP's position in MAGNITE 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 Q3

MGNI was reported at 0.53% of portfolio in the most recent visible filing.

High-water mark
Peak Conviction
1.17% in 2025 Q2

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

Time in book
Holding Window
2024 Q1 to 2025 Q3

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.

MGNI stock page ARDSLEY ADVISORY PARTNERS LP fund profile ARDSLEY ADVISORY PARTNERS LP full holdings
How ARDSLEY ADVISORY PARTNERS LP held MGNI — position size vs. price
% of Fund (quarterly)    MGNI price (quarter-end, indexed to 100)    SPY (indexed to 100)    QQQ (indexed to 100)
📋 Quarterly Holdings History 7 quarters  ▾
Quarter Action Sold % After 3M Timing Shares Change Chg % % of Fund Mkt Value Filed Price (Filed)
2025 Q3 ADDED — — — 195,000 +135,000 +225.0% 0.53% $4.2M 2025-11-14 $14.15
2025 Q3 REDUCED 83.8% -24.5% ✅ 60,000 -310,000 -83.8% 0.16% $1.3M 2025-11-14 $14.15
2025 Q2 ADDED — — — 370,000 +120,000 +48.0% 1.17% $8.9M 2025-08-14 $23.59
2025 Q1 ADDED — — — 250,000 +94,000 +60.3% 0.55% $2.9M 2025-05-15 $15.88
2025 Q1 ADDED — — — 156,000 +23,050 +17.3% 0.34% $1.8M 2025-05-15 $15.88
2024 Q2 ADDED — — — 132,950 +40,950 +44.5% 0.26% $1.8M 2024-08-14 $12.52
2024 Q1 ADDED — — — 92,000 +67,250 +271.7% 0.14% $989K 2024-05-15 $9.80
5 older quarters hidden  —  Sign in free or upgrade to Premium to see full history

🏢 Other funds also holding MGNI

As of 2026 Q1 — sorted by position size

Kopion Asset Management, LLC 3Y 7.91% Maestria Partners LLC 5.91% P.A.W. CAPITAL CORP 3Y 7Y 5.5% 1492 Capital Management LLC 3Y 7Y 1.54% PERKINS CAPITAL MANAGEMENT INC 3Y 7Y 1.33% Penbrook Management LLC 3Y 7Y 1.01% STEINBERGANNA WEALTH MANAGEMENT 0.39% Bayforest Capital Ltd 0.18% Ledgewood Wealth Advisors, LLC 0.08% Murphy & Mullick Capital Management Corp 0.08%

FAQ About ARDSLEY ADVISORY PARTNERS LP and MGNI

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

How long has ARDSLEY ADVISORY PARTNERS LP reported owning MGNI?

ARDSLEY ADVISORY PARTNERS LP reported MGNI across 7 quarterly 13F filings, from 2024 Q1 through 2025 Q3.

What was the largest reported MGNI position in ARDSLEY ADVISORY PARTNERS LP's portfolio?

The largest reported portfolio weight for MGNI was 1.17% in 2025 Q2.

What is the latest reported MGNI position on this page?

The most recent filing on this page is 2025 Q3, when ARDSLEY ADVISORY PARTNERS LP reported 195,000 shares, equal to 0.53% of portfolio, with an estimated market value of $4.2M.

What does the chart on this MGNI ownership page compare?

The chart compares ARDSLEY ADVISORY PARTNERS LP's quarterly MGNI 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 ARDSLEY ADVISORY PARTNERS LP time their MGNI position?

Based on 13F filing dates vs. subsequent MGNI price moves, ARDSLEY ADVISORY PARTNERS LP correctly timed 7 out of 11 reported position changes (64%). The annualised alpha on MGNI relative to SPY over the holding period was -6.1%.

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