Where is this manager's return actually coming from — replicable market and sector exposure, or stock selection? Pulled live from the latest 13F and decomposed through the ERM3 cascade. The stock-selection residual — the return remaining after the model's specified market, sector, and subsector exposures — is the component that persists out of sample.
Modeled AUM
$177M
Holdings
22
Top-10 weight
98%
Modeled AUM is the sum of disclosed long US equity positions that join the ERM3 universe — not firm-wide AUM. 13F books omit shorts, most derivatives, and non-US holdings.
Evidence
13F · disclosed-long analysis
Holdings as of
2025-12-31
Filed
2026-03-16
Model
ERM3 v3.0
Form 13F discloses long US positions only, on a delayed filing schedule; short positions and most derivatives are not reported.
Selection signature
Exposure-driven
23% of BERKSHIRE HATHAWAY INC's risk is stock-specific — the structural read. Stock selection added 5% 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
69%
23%
▸Key
Market
Sector
Subsector
Style tilt
Residual risk
At a glance
Selection signature
23% of risk
Exposure-driven
Replicable exposure
76%
Mostly buyable
Mandate style
Large Blend
Multi-style
Concentration
eff. N 3.9
Concentrated
Peer rank · Mega tier
#23 / 420
Return attribution
AIBERKSHIRE HATHAWAY INC's +19.1% trailing-year return was led by market beta (+17.8% market); stock selection contributed -1.0%.
Layer
Detail
1M
3M
6M
1Y
Gross return
total realized
-0.8%
+7.3%
+15.0%
+19.1%
− Market
broad-market beta
+0.1%
+2.4%
+10.0%
+17.8%
− Sector
sector timing
+0.9%
-0.0%
-2.3%
2 · Stock-selection residual
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
-1.0%
trailing, gross — residual after market / sector / subsector
Residual risk share
42%
stock-specific share of portfolio variance
Return from selection
5%
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)
0.63
Effective styles
1.6
Effective N (positions)
3.9
5 · Peer context
#23 / 420
In the Mega AUM cohort by top10 weight sum (1m).
100% of reported AUM is in the ERM3 model universe; attribution and residual 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 stock selection? Pulled live from the latest 13F and decomposed through the ERM3 cascade. The stock-selection residual — the return remaining after the model's specified market, sector, and subsector exposures — is the component that persists out of sample.
Modeled AUM
$177M
Holdings
22
Top-10 weight
98%
Modeled AUM is the sum of disclosed long US equity positions that join the ERM3 universe — not firm-wide AUM. 13F books omit shorts, most derivatives, and non-US holdings.
Evidence
13F · disclosed-long analysis
Holdings as of
2025-12-31
Filed
2026-03-16
Model
ERM3 v3.0
Form 13F discloses long US positions only, on a delayed filing schedule; short positions and most derivatives are not reported.
Selection signature
Exposure-driven
23% of BERKSHIRE HATHAWAY INC's risk is stock-specific — the structural read. Stock selection added 5% 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
69%
23%
▸Key
Market
Sector
Subsector
Style tilt
Residual risk
At a glance
Selection signature
23% of risk
Exposure-driven
Replicable exposure
76%
Mostly buyable
Mandate style
Large Blend
Multi-style
Concentration
eff. N 3.9
Concentrated
Peer rank · Mega tier
#23 / 420
Return attribution
AIBERKSHIRE HATHAWAY INC's +19.1% trailing-year return was led by market beta (+17.8% market); stock selection contributed -1.0%.
Layer
Detail
1M
3M
6M
1Y
Gross return
total realized
-0.8%
+7.3%
+15.0%
+19.1%
− Market
broad-market beta
+0.1%
+2.4%
+10.0%
+17.8%
− Sector
sector timing
+0.9%
-0.0%
-2.3%
2 · Stock-selection residual
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
-1.0%
trailing, gross — residual after market / sector / subsector
Residual risk share
42%
stock-specific share of portfolio variance
Return from selection
5%
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)
0.63
Effective styles
1.6
Effective N (positions)
3.9
5 · Peer context
#23 / 420
In the Mega AUM cohort by top10 weight sum (1m).
100% of reported AUM is in the ERM3 model universe; attribution and residual 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.
-5.0%
− Subsector
industry timing
+0.1%
+0.4%
+1.0%
+6.3%
= Buyable exposure
replicable in ETFs
+1.1%
+2.7%
+8.7%
+19.1%
Stock selection (residual return)
net of market/sector/subsector · cohort evidence: persists OOS
-2.0%
+4.4%
+6.3%
-1.0%
Risk attribution
AI23% of the book's risk is stock-specific; the rest is broad-market (69%) and sector exposure.
Layer
Detail
Full
Recent
− Market
broad-market beta
69%
41%
− Sector
sector exposure
5%
16%
− Subsector
industry exposure
2%
1%
= Buyable exposure
replicable
76%
57%
Residual risk share
stock-specific share of variance — where selection can show up