Mizuho Securities Co. Ltd. ARM — ARM HOLDINGS PLC

Ownership history in Mizuho Securities Co. Ltd.  ·  8 quarters on record

AI Ownership Summary

Mizuho Securities Co. Ltd. reported ARM HOLDINGS PLC (ARM) in 8 quarterly 13F filings from 2023 Q4 through 2025 Q3. Peak portfolio weight reached 10.72% in 2023 Q4. The latest visible filing shows ARM at 0.97% 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 ARM ownership page tells you

This page is designed to answer the real investor question behind a 13F filing: how meaningful was Mizuho Securities Co. Ltd.'s position in ARM HOLDINGS PLC, 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

ARM was reported at 0.97% of portfolio in the most recent visible filing.

High-water mark
Peak Conviction
10.72% in 2023 Q4

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

Time in book
Holding Window
2023 Q4 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.

ARM stock page Mizuho Securities Co. Ltd. fund profile Mizuho Securities Co. Ltd. full holdings
How Mizuho Securities Co. Ltd. held ARM — position size vs. price
% of Fund (quarterly)    ARM price (quarter-end, indexed to 100)    SPY (indexed to 100)    QQQ (indexed to 100)
📋 Quarterly Holdings History 8 quarters  ▾
Quarter Action Sold % After 3M Timing Shares Change Chg % % of Fund Mkt Value Filed Price (Filed)
2025 Q3 REDUCED 90.9% -21.9% ✅ 1,000 -9,970 -90.9% 0.97% $141K 2025-10-30 $165.45
2025 Q2 ADDED — — — 10,970 +3,920 +55.6% 6.41% $1.8M 2025-08-12 $142.39
2025 Q1 ADDED — — — 7,050 +5,330 +309.9% 8.93% $753K 2025-04-22 $100.55
2024 Q4 REDUCED 87.5% -13.4% ✅ 1,720 -12,060 -87.5% 3.27% $217K 2025-02-12 $155.41
2024 Q3 REDUCED 25.1% -12.0% ✅ 13,780 -4,620 -25.1% 4.85% $2.0M 2024-11-06 $144.68
2024 Q2 ADDED — — — 18,400 +11,220 +156.3% 7.00% $3.0M 2024-08-01 $121.51
2024 Q1 REDUCED 82.0% +27.1% ❌ 7,180 -32,630 -82.0% 4.94% $897K 2024-05-02 $98.00
2023 Q4 INITIATED — — — 39,810 — — 10.72% $3.0M 2024-02-02 $71.00

🏢 Other funds also holding ARM

As of 2026 Q1 — sorted by position size

Tensor Edge Capital, LLC 7.53% TRAN CAPITAL MANAGEMENT, L.P. 3Y 7Y 5.67% Defender Capital, LLC. 3Y 5.31% Robocap Asset Management Ltd 4.62% DOCK STREET ASSET MANAGEMENT INC 3Y 7Y 3.42% Gunderson Capital Management LLC 3Y 2.85% Westend Capital Management, LLC 3Y 7Y 2.44% Haven Capital Group, Inc. 2.42% WILLNER & HELLER, LLC 3Y 1.4% Tower View Wealth Management LLC 3Y 7Y 1.37%

FAQ About Mizuho Securities Co. Ltd. and ARM

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

How long has Mizuho Securities Co. Ltd. reported owning ARM?

Mizuho Securities Co. Ltd. reported ARM across 8 quarterly 13F filings, from 2023 Q4 through 2025 Q3.

What was the largest reported ARM position in Mizuho Securities Co. Ltd.'s portfolio?

The largest reported portfolio weight for ARM was 10.72% in 2023 Q4.

What is the latest reported ARM position on this page?

The most recent filing on this page is 2025 Q3, when Mizuho Securities Co. Ltd. reported 1,000 shares, equal to 0.97% of portfolio, with an estimated market value of $141K.

What does the chart on this ARM ownership page compare?

The chart compares Mizuho Securities Co. Ltd.'s quarterly ARM 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 Mizuho Securities Co. Ltd. time their ARM position?

Based on 13F filing dates vs. subsequent ARM price moves, Mizuho Securities Co. Ltd. correctly timed 5 out of 7 reported position changes (71%). The annualised alpha on ARM relative to SPY over the holding period was +33.7%.

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