Where is this manager's return actually coming from — replicable market and sector exposure, or genuine stock selection? Pulled live from the latest 13F and decomposed through the ERM3 cascade. The stock-selection residual is the one component that persists out of sample.
Modeled AUM
$176.5B
Holdings
22
Top-10 weight
98%
As of
2025-12-31
Filed
2026-03-16
Selection signature
Exposure-driven
23% of BERKSHIRE HATHAWAY INC's risk is stock-specific — the structural read. Stock selection added 6% of the trailing return (which swings with the window). The rest is buyable market, sector, and style exposure — a descriptive read, not a recommendation.
Risk decomposition
70%
23%
▸Key
Market
Sector
Subsector
Stock selection
At a glance
Selection signature
23% of risk
Exposure-driven
Replicable exposure
77%
Mostly buyable
Mandate style
Large Blend
Single-style
Concentration
eff. N 3.9
Concentrated
Peer rank · Mega tier
#34 / 420
Return attribution
AIBERKSHIRE HATHAWAY INC's +19.1% trailing-year return was led by market beta (+17.5% market); stock selection contributed +1.1%.
Layer
Detail
1M
3M
6M
1Y
Gross return
total realized
-0.8%
+7.3%
+15.0%
+19.1%
− Market
broad-market beta
+0.1%
+2.3%
+9.9%
+17.5%
− Sector
sector timing
+0.9%
-0.1%
-2.4%
2 · Residual skill score
The stock-selection residual — return left after market, sector, subsector, and style are stripped away. This is the component the research shows persists out of sample (forward Q5−Q1 +2.3pp, t≈3.4), while sector- and style-timing do not.
Stock-selection return
+1.1%
trailing, gross — residual after market / sector / subsector
Residual risk share
49%
stock-specific share of portfolio variance
Return from selection
6%
of gross return this window
Out-of-sample persistence
+2.3pp · t≈3.4
forward Q5−Q1 across the study cohort — not this manager
Gross ranking signal within mandate; net-of-fee outcomes depend on fees and implementation. Not a claim of net-of-fee outperformance. See the evidence →
4 · Mandate fit
Dominant style
Large Blend
Style concentration (HHI)
0.85
Effective styles
1.2
Effective N (positions)
3.9
5 · Peer context
#34 / 420
In the Mega AUM cohort by aum erm3 (1m).
65% of reported AUM is in the ERM3 model universe; attribution and skill shares cover that sleeve.
Run this on your managers
This is a live example. Send us a roster — 13F managers or your own holdings sleeves — and we'll return a Manager Skill Review and a board-ready IC memo for each. Print or PDF this page for the memo format.
Live data from SEC Form 13F via the RiskModels ERM3 model, filed 2026-03-16. Figures are gross, holdings-derived, and within-mandate. Informational use only — not investment advice.
Manager Skill Review · Live example
BERKSHIRE HATHAWAY INC
Where is this manager's return actually coming from — replicable market and sector exposure, or genuine stock selection? Pulled live from the latest 13F and decomposed through the ERM3 cascade. The stock-selection residual is the one component that persists out of sample.
Modeled AUM
$176.5B
Holdings
22
Top-10 weight
98%
As of
2025-12-31
Filed
2026-03-16
Selection signature
Exposure-driven
23% of BERKSHIRE HATHAWAY INC's risk is stock-specific — the structural read. Stock selection added 6% of the trailing return (which swings with the window). The rest is buyable market, sector, and style exposure — a descriptive read, not a recommendation.
Risk decomposition
70%
23%
▸Key
Market
Sector
Subsector
Stock selection
At a glance
Selection signature
23% of risk
Exposure-driven
Replicable exposure
77%
Mostly buyable
Mandate style
Large Blend
Single-style
Concentration
eff. N 3.9
Concentrated
Peer rank · Mega tier
#34 / 420
Return attribution
AIBERKSHIRE HATHAWAY INC's +19.1% trailing-year return was led by market beta (+17.5% market); stock selection contributed +1.1%.
Layer
Detail
1M
3M
6M
1Y
Gross return
total realized
-0.8%
+7.3%
+15.0%
+19.1%
− Market
broad-market beta
+0.1%
+2.3%
+9.9%
+17.5%
− Sector
sector timing
+0.9%
-0.1%
-2.4%
2 · Residual skill score
The stock-selection residual — return left after market, sector, subsector, and style are stripped away. This is the component the research shows persists out of sample (forward Q5−Q1 +2.3pp, t≈3.4), while sector- and style-timing do not.
Stock-selection return
+1.1%
trailing, gross — residual after market / sector / subsector
Residual risk share
49%
stock-specific share of portfolio variance
Return from selection
6%
of gross return this window
Out-of-sample persistence
+2.3pp · t≈3.4
forward Q5−Q1 across the study cohort — not this manager
Gross ranking signal within mandate; net-of-fee outcomes depend on fees and implementation. Not a claim of net-of-fee outperformance. See the evidence →
4 · Mandate fit
Dominant style
Large Blend
Style concentration (HHI)
0.85
Effective styles
1.2
Effective N (positions)
3.9
5 · Peer context
#34 / 420
In the Mega AUM cohort by aum erm3 (1m).
65% of reported AUM is in the ERM3 model universe; attribution and skill shares cover that sleeve.
Run this on your managers
This is a live example. Send us a roster — 13F managers or your own holdings sleeves — and we'll return a Manager Skill Review and a board-ready IC memo for each. Print or PDF this page for the memo format.
Live data from SEC Form 13F via the RiskModels ERM3 model, filed 2026-03-16. Figures are gross, holdings-derived, and within-mandate. Informational use only — not investment advice.
-5.4%
− Subsector
industry timing
+0.1%
+0.4%
+1.0%
+6.0%
= Buyable exposure
replicable in ETFs
+1.2%
+2.6%
+8.6%
+18.2%
Stock selection
residual skill · persists OOS
-2.0%
+4.7%
+6.4%
+1.1%
Risk attribution
AI23% of the book's risk is stock-specific; the rest is broad-market (70%) and sector exposure.