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Why Your Stock-Only Portfolio is Vulnerable (And How I Fixed It With Engineering)

Published: Feb 04, 2026 Walter
Why Your Stock-Only Portfolio is Vulnerable (And How I Fixed It With Engineering)

How an aerospace engineer applied systems thinking to investing and built the tool he couldn't find.


As an aerospace engineer turned investor, I’ve always approached finance the same way I approach flight dynamics: build systems that withstand turbulence, minimize failure points, and deliver reliable performance.

Early on, I thought "diversification" just meant buying different stocks. But after years of refining my own portfolio, I realized that wasn't enough. True resilience doesn't come from owning 50 different tech stocks; it comes from owning assets that behave differently.

The Flaw in Traditional Portfolios

My journey started with classics like Benjamin Graham's "The Intelligent Investor"(#ad), which taught me the value of safety margins. But as I dug into macro trends by reading Ray Dalio’s "Principles"(#ad) and studying market cycles, I saw the bigger picture.

In 2026, with lingering inflation and geopolitical tension, stock-only portfolios are vulnerable. When the market tanks (like in 2022), most equities sink together. Correlations approach 1.0, and your "diversified" stock basket offers zero protection.

I realized I needed a "Holy Grail" portfolio one balanced across economic regimes:

  • Gold for inflation protection and stability.
  • Stocks for long-term growth.
  • Crypto for asymmetric upside potential.

The 33/33/33 Solution (And the Problem with Tracking It)

This research led to my personal allocation: roughly one-third physical gold, one-third global equities, and one-third crypto.

It worked. During stock crashes, gold held steady. During bull runs, crypto surged. But managing it was a nightmare. I had a brokerage app for stocks, a hardware wallet for crypto, and a spreadsheet that was always out of date.

I couldn't find a tool that respected every asset class equally. Stock apps treated crypto as an afterthought; crypto apps ignored my ETFs.

So, I Built FinSxS

FinSxS (Financial Side-by-Side) was born from frustration. It is designed to be the single source of truth for the cross-asset investor.

Unlike mainstream trackers that silo your assets, FinSxS unifies them:

  • Global Allocation at a Glance: See your true net worth split across Crypto, ETFs, and Equities in one pie chart. Spot overexposure instantly.
  • Multi-Currency Normalization: Have EUR stocks, USD crypto, and GBP cash? We normalize everything to your base currency automatically using ECB rates.
  • Relative Performance: Stop guessing if your diversification is working. Benchmark your entire portfolio against the S&P 500 or custom indices.
  • Privacy-First: Your data is yours. We don't sell it, and we don't share it.

See Your Full Financial Picture

You don't need to use my 33/33/33 split to benefit from FinSxS. Whether you have a classic 60/40 portfolio or a complex mix of alts and equities, you need to see how they interact.

Stop juggling apps and broken spreadsheets. Try FinSxS. Free sign-up, no card needed. Explore the Global Portfolio Dashboard or start tracking.

Follow @Fin_SxS on X for tips. Feedback?


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