LatticeworkTHE EVIDENCE DESK
Decision record· ADD · Q2 2026

AltaRock Partners increased MSFT by 25%. Was it still actionable?

The filing established that AltaRock Partners increased MSFT shares by 25.0%. It did not reveal transaction dates, execution prices, or the manager's reason for the change.

Share𝕏in

Latticework verdict

Context, not a trade alert

High-conviction increase. Low timing precision.

A 20.5% reported portfolio weight makes this increase material. Pattern: one-quarter change. But the disclosed change could have occurred anywhere in the quarter and was published 48 days after quarter end, making it 48–138 days old at disclosure. Use it to investigate the thesis, not to copy an entry or exit.

Inspect the original SEC filing ↗See the disclosure delay ↓

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Reported shares
+25.0%
+466,945
Portfolio weight
20.5%
from 16.8%
Quarter-end value
$871M
not purchase cost
Signal age
48–138d
when disclosed

What the clock tells us

Apr 1, 2026

Change window opens

The net change could begin here—or later.

Jun 30, 2026

Quarter-end snapshot

The filing measures shares and fair value on this date.

Aug 17, 2026

Public disclosure

The snapshot arrived 48 days after quarter end.

The filing does not identify transaction dates inside the Apr 1, 2026–Jun 30, 2026 change window.

What we know

  • Shares: 1,867,537 → 2,334,482, a net increase of 466,945.
  • Weight: MSFT moved from 16.8% to 20.5% of AltaRock Partners's reported long U.S. equity book.
  • Pattern: The latest move did not extend a three-quarter directional share-count pattern. Reported weight path: 2025Q1 19.5% → 2025Q2 23.4% → 2025Q3 24.3% → 2025Q4 19.7% → 2026Q1 16.8% → 2026Q2 20.5%.
  • Valuation snapshot: the filing implies $373.02 per share at quarter end. That is reported fair value, not AltaRock Partners's entry price.

Decision test

Meaningful?Yes
Large share change and material book weight. Pattern: one-quarter change.
Timely?No
The information was 48–138 days old at publication.
Corroborated?Mixed
9 material buy/add and 13 trim/exit signals across the cohort.
Copyable?No
No trade dates, cost basis, rationale, or manager-specific constraints.

Source versions and follow-through

What was recorded, and when?

First registered 2026-09-07 · source version 1, recorded 2026-09-07. The source filing was public on 2026-08-17; registration here happened separately.

Prospective observation · tracking

This version's clock begins at the first shared market close strictly after 2026-09-07. The filing date alone cannot backdate a selection. Earlier post-filing returns remain in the retrospective tracker below.

4.8% stock · 0.7% SPY · +4.0 percentage points vs SPY · 2026-09-08–2026-10-02 (19 closes).

Inspect source versions and corrections (1)

  1. Version 1 · 2026-09-07

    First prospective registration; earlier filing returns remain retrospective.

    ADD · 16.75% before → 20.54% after.

    Original SEC source ↗

    Source snapshot SHA-256 54696a260dce2a2eac84c7beb27f63c2cc206dcd68615bcdd349a834a41ecb77

30 dated prospective observations retained. Source changes restart the revised claim's clock; previous versions and observations stay in the registry.

Download the source and observation registry

Registration versions are retained in this project's history, not certified by an independent timestamp authority. This is an editorial sample with overlapping stocks, not a prediction or a manager portfolio backtest.

Retrospective outcome tracker · tracking

What happened after disclosure?

33 sessions · through Oct 2, 2026

Measured from the first shared market close after the SEC filing—not from the manager's unknown entry or exit price.

MSFT
+7.7%
SPY
+0.5%
Vs SPY
+7.1%

The disclosed direction is supported so far.

Early performance can reverse. This is observation, not a verdict on the manager or the security.

The cohort did not move as one

Tracked managers disclosed 9 material buy/add signals and 13 trim/exit signals in MSFT. Quarter-end cohort ownership moved from 37 to 34. This was disagreement, not consensus.

Source trail and limits

Original SEC filing ↗Full Q2 2026 diff →MSFT researchAltaRock Partners portfolio →Outcome prices ↗
  • A 13F reports quarter-end holdings, not transaction dates or execution prices.
  • The net share change may represent multiple purchases and sales during the quarter.
  • Portfolio weight covers AltaRock Partners's disclosed long U.S. 13F book, not its full assets or exposures.
  • Quarter-end value per share is reported fair value divided by shares; it is not the manager's cost basis.

SEC accession 0001104659-26-097527 · CUSIP 594918104

Primary-source research, not investment advice.