Portfolio Construction

4 min read

Portfolio Construction

Portfolio construction is assembling a collection of investments matched to your goals, timeline, and risk tolerance --- the architecture of your investment life.

What is it?

A portfolio is not a collection of individual bets. It is a system designed to achieve a specific outcome over a specific time horizon at a specific risk level. Portfolio construction applies diversification and asset-class knowledge to build that system.1

The core decision is asset allocation --- the percentage split between asset classes (equities, bonds, real estate, cash). Research consistently shows that asset allocation explains approximately 90% of the variation in portfolio returns over time. Individual security selection (which stocks, which bonds) explains roughly 10%.2

This means the most important investment decision is not which stocks to buy but how much to put in stocks vs bonds vs other asset classes. Get the allocation right and the details matter less.

In plain terms

Portfolio construction is the blueprint of your investment house. Asset allocation is the foundation. Individual investments are the furniture. You can have ugly furniture in a well-built house and be fine. You cannot have beautiful furniture in a house with a cracked foundation.

How does it work?

1. Match allocation to time horizon

Time horizonSuggested equity allocationRationale
30+ years80-100%Long time to recover from downturns
15-30 years60-80%Balance growth with stability
5-15 years40-60%Reduce volatility as timeline shortens
< 5 years0-30%Capital preservation priority

A common rule of thumb: equity allocation ≈ 110 minus your age. At 30: 80% equities. At 50: 60%. This is a starting point, not a law.

2. Core-satellite approach

Core (80-90% of portfolio): Low-cost, diversified index funds. Global equity index + bond index. This captures the market return with minimal fees and maximum diversification.

Satellite (10-20%): Higher-conviction positions. Individual stocks you believe in, sector ETFs, impact investments, your own ventures. This is where personal conviction and values-aligned investing live.

3. Rebalancing

Markets move. A 70/30 stock/bond portfolio that rises in a bull market becomes 80/20. Rebalancing means selling what has grown (stocks) and buying what has lagged (bonds) to return to target. This is counterintuitive --- you are selling winners and buying losers --- but it enforces the discipline of buying low and selling high.

Rebalance annually or when allocation drifts more than 5% from target. For someone with ADHD, automatic rebalancing (offered by robo-advisors and some 3a providers) removes the decision entirely.

4. Swiss-specific considerations

  • 3a invested (VIAC, Frankly, finpension): maximise equity allocation within the 3a for long-term growth. The tax advantage compounds the return.
  • Currency exposure: Swiss franc is strong. Global equity funds expose you to USD, EUR, etc. Some hedging may be appropriate for the bond portion. Equity currency exposure over 20+ years tends to wash out.
  • Pillar 2: your pension fund’s allocation is not under your control but counts as part of your total portfolio. If your Pillar 2 is conservative (heavy bonds), you can be more aggressive in your personal investments.

Check your understanding

Where this concept fits

Where this concept fits 

graph TD
    DV[Diversification] --> PC[Portfolio Construction]
    AC[Asset Class] --> PC
    RR[Risk and Return] --> PC
    FI[Financial Independence] --> PC
    PC --> BF[Behavioral Finance]
    style PC fill:#4a9ede,color:#fff

Sources

Footnotes

  1. Markowitz, H. (1952). “Portfolio Selection.” Journal of Finance. The theoretical foundation. ↩

  2. Brinson, G. P., Hood, L. R., & Beebower, G. L. (1986). “Determinants of Portfolio Performance.” Financial Analysts Journal, 42(4), 39-44. The landmark study showing asset allocation explains ~90% of return variation. ↩

Graph View

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