REVEALING THE ILLUSION OF DIVERSIFICATION

You Think You Own 500 Stocks. The Math Shows You Only Own 5.

Holding an S&P 500 fund in your 401(k), Nasdaq 100 in your Roth IRA, Total Market in your taxable brokerage, and company RSUs doesn't give you 500 stocks. You own duplicate shares of the same 5 tech giants four times over. Effective-N unrolls your funds down to the leaf level to compute your true diversification.

Effective-N Engine • Cinematic 4K Commercial
0:15 Commercial • Quantitative Portfolio Analysis
0:00 / 0:15
87%
Hidden Mega-Cap Drag
Of multi-account retail investors suffer from extreme undetected tech concentration.
44.8%
VOO vs QQQ Overlap
Identical underlying holdings between standard S&P 500 and Nasdaq 100 funds.
100%
Local & Private
On-device Android SQLite processing. Zero bank passwords, zero cloud data tracking.
1-Click
Fidelity CSV Import
Instant parsing of positions with automatic cash sweep and CIT proxy unrolling.
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The "4 Fruit Smoothies" Trap

Imagine ordering 4 different smoothies at a café named "Tropical Blend", "All-Star Punch", "Island Delight", and "Super Boost". You think you're getting a rich variety of fruits—until you look into the blender and discover all 4 smoothies are 85% pure banana! That is exactly what happens when you hold VOO, QQQ, VTI, and tech stocks together.

Mathematical Decomposition

The 4-Stage "Look-Through" Pipeline

How Effective-N de-cloaks your true portfolio risk across multiple accounts, custodians, and fund wrappers.

STAGE 01
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Multi-Account Aggregation

Ingests holdings across your 401(k), Roth IRA, Traditional IRA, Taxable Brokerage, HSA, and Tech RSUs into one unified ledger.

Consolidates M accounts & N custodians
STAGE 02
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ETF Wrapper Expansion

Peels back index wrappers (VOO, QQQ, VTI, VGT, SMH, SCHD, VXUS) down to every underlying fractional share.

Unrolls Top 50+ constituents per ETF
STAGE 03
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Leaf-Level Issuer Merging

Merges identical corporate issuers across funds (Direct NVDA + VOO NVDA + QQQ NVDA + VTI NVDA) into total aggregate exposure.

Computes true net corporate weights $w_i$
STAGE 04
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Inverse Herfindahl (Neff)

Applies the quantitative inverse concentration formula to reveal your true number of independent holdings.

Neff = 1 / Σ(wi2)
Interactive Portfolio Engine

The Diversification Reality Check

Test a real-world multi-account portfolio below. Watch how nominal holdings collapse under quantitative look-through analysis.

lookthrough_engine.kt · v2.0
SIMULATING...
Fee & Redundancy Inspector

Fund Overlap & Duplicate Drag Matrix

Click common ETF pairings below to inspect how much identical underlying stock you are paying double fees to own.

VOO vs QQQ
S&P 500 vs Nasdaq 100
VOO vs VGT
S&P 500 vs Info Tech
VTI vs SPY
Total US vs S&P 500
SCHD vs VOO
Dividend vs S&P 500
44.8%
Weight Overlap

⚠️ SEVERE REDUNDANCY

VOO (S&P 500) vs QQQ (Nasdaq 100)

Nearly half of every dollar you invest in QQQ is purchasing the exact same mega-cap stocks already held in VOO. You are paying QQQ's higher 0.20% expense ratio for stocks you already own in VOO at 0.03%.

Top Overlapping Corporate Heavyweights:
Effective-N Recommendation: Instead of pairing VOO with QQQ, pair VOO with International (VXUS) or Small-Cap Value (AVUV) to achieve genuine orthogonal diversification.
Macro Stress Testing

Macro Crash & Volatility Simulator

When a market shock hits, a "fake diversified" portfolio crashes as hard as a single tech stock. Compare stress test resilience below.

📉
Tech Growth Shock
-25% Big Tech / Semis
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Rate Surge (+150 bps)
Duration & Tech multiple hit
⛽
Stagflation Crunch
-18% Stocks / +12% Energy
🛡️
Defensive Recession
Flight to Quality Treasuries
🔴 The Retail Illusion (Nominal 500) -22.8%
Estimated Loss on $200,000 portfolio: -$45,600
🟢 Effective-N Balanced (Real Neff = 28.4) -4.2%
Estimated Loss on $200,000 portfolio: -$8,400 (Saved $37,200)

Why this happens: In a Tech Growth shock, the Retail Illusion portfolio experiences severe drawdowns because 63% of its total capital is secretly concentrated in just 3 tech companies across 4 accounts. The Effective-N balanced portfolio protects your capital through true asset class dispersion.

Google Gemini 2.5 Flash

Interactive Quantitative AI Copilot

Click any question below to see how Effective-N translates institutional math into crystal-clear plain English.

"Explain Effective N (N_eff) like I'm 10"
"Why does holding VOO and QQQ create duplicate risk?"
"What is Asset Location and how does it save taxes?"
"Is my financial data private when importing Fidelity CSVs?"
👤
"Explain Effective N (N_eff) like I'm 10"
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Zero-Credential Architecture

100% Local-First Privacy Promise

Your financial life is nobody else's business. See how Effective-N protects your data compared to cloud-based wealth trackers.

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Cloud Wealth Apps (Plaid / Web)

  • Requires your brokerage passwords and 2FA credentials.
  • Stores your net worth and holdings on vulnerable remote cloud servers.
  • Sells anonymized user spending & investment habits to third-party data brokers.
  • Vulnerable to server outages, data leaks, and credential stuffing attacks.
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Effective-N On Android

  • Zero Bank Passwords: 1-click parse of your exported CSV file on your phone.
  • 100% On-Device SQLite: All calculations, holdings, and accounts live in private app storage.
  • No Cloud Backend: We have no user databases, no login servers, and no data tracking.
  • Direct Gemini AI: If enabled, calls Google AI Studio directly using your own private API key in EncryptedSharedPreferences.