Illustrative Scenario: Multi-Asset Allocation for a Tech Founder

Illustrative scenario. This is a hypothetical example written to show how cross-border planning can work. It does not describe a real Serra client and reports no real outcomes.

How a planner could help a Barcelona-based tech entrepreneur diversify an 80% concentrated stock position into a balanced global portfolio — without triggering unnecessary tax events.

The Situation

In this scenario, a successful tech founder based in Barcelona, had built a company that went through a Series B funding round, followed by a secondary share sale. The result: approximately €6.5 million in liquid wealth, of which over 80% was concentrated in a single US-listed tech stock received as part of the secondary transaction.

The client knew the concentration was dangerous. A single negative earnings report or sector rotation could wipe out years of wealth creation in weeks. But selling the entire position at once would trigger approximately €400,000 in capital gains taxes and potentially push the stock price down (the position represented meaningful volume relative to average daily trading).

The question was not whether to diversify — it was how to do it intelligently.

The Risk Assessment

Before designing the diversification strategy, we quantified exactly what the concentration risk looked like:

• Single-stock VaR (95%, 1-month): €780,000 — meaning in the worst 5% of months, the client could expect to lose at least €780,000
• Maximum historical drawdown for the stock: -62% during the 2022 tech correction, which would have represented a loss of €3.2 million
• Correlation with client's other assets: 0.85 — the remaining 20% of the portfolio was in other US tech names, meaning "diversified" assets would likely fall simultaneously
• Effective portfolio diversification: Essentially zero. Despite holding multiple positions, the portfolio behaved as if it were a single concentrated bet on US tech growth

We presented these numbers in euro terms rather than percentages. Hearing "you could lose €3.2 million in a tech correction" is far more impactful than "your portfolio could decline 62%."

The Strategy: Phased Diversification

The plan sets out a 12-month diversification plan with three components:

Phase 1: Tax-Optimized Selling (Months 1-4)

Rather than selling the entire position at once, we implemented a systematic selling program:

• VWAP-based execution: Selling a fixed euro amount daily, executed at the volume-weighted average price to minimize market impact
• Tax-loss harvesting coordination: Timing sales to offset gains against losses in other positions, reducing the net tax impact by approximately €85,000
• Bracket management: Structuring sales across two tax years to keep the client in a lower capital gains bracket in each year (Spain's capital gains rates are progressive: 19% on the first €6,000, 21% on €6,000–50,000, 23% on €50,000–200,000, 27% on €200,000–300,000, and 28% above €300,000. In the US, long-term capital gains rates range from 0% to 20% depending on taxable income, plus a potential 3.8% Net Investment Income Tax for higher earners)

By spreading the sales over two tax years and harvesting available losses, the effective tax rate on realized gains dropped from an estimated 26.5% to approximately 21.8%.

Phase 2: Core Portfolio Construction (Months 2-8)

As sale proceeds accumulated, we deployed capital into a diversified global portfolio designed around the client's risk profile (moderate-aggressive, 15+ year horizon, no near-term liquidity needs):

Target allocation:

• Global developed market equities (30%) — via low-cost ETFs tracking MSCI World, with deliberate underweighting of US tech to offset remaining concentrated position
• Emerging market equities (10%) — broad EM exposure with an overweight to India and Southeast Asia as a counterbalance to the client's existing LATAM and US exposure
• Global fixed income (15%) — investment-grade corporate bonds and inflation-linked sovereign bonds
• European real estate (15%) — through a diversified REIT portfolio and one direct co-investment in a Barcelona commercial property
• Private credit (10%) — senior secured lending fund targeting 8-9% net yield
• Alternative strategies (10%) — global macro hedge fund and a commodity trend-following allocation
• Cash buffer (10%) — maintained during the transition, gradually deployed as opportunities arose

Phase 3: Monitoring and Adjustment (Months 8-12)

The final phase focused on fine-tuning the portfolio and establishing ongoing management protocols:

• Monthly rebalancing review — checking all positions against ±3% bands
• Quarterly risk assessment — updated VaR, stress tests, and correlation analysis
• Annual tax planning — coordinating with the client's Spanish tax advisor on Modelo 720 reporting and optimal gain/loss realization timing

Key Lessons

1. Concentration risk is not a theoretical concept. It is a specific, quantifiable threat that can be expressed in euro terms. Presenting risk as "you could lose €3.2M" rather than "your stock is volatile" made the decision to diversify straightforward.

2. Tax optimization is not about avoidance — it is about timing. Spreading sales across two tax years and coordinating with loss harvesting can lower the tax cost. This required proactive planning, not reactive selling.

3. Diversification reduces return expectations — and that is the point. The client accepted a lower expected return (8.5% vs. 12%) in exchange for dramatically lower risk. For someone who has already created significant wealth, preserving it is more valuable than trying to double it again.

4. Behavioral coaching matters. The hardest moments were when the concentrated stock rallied during the selling program. The client questioned whether diversification was necessary. Having a pre-committed plan with clear rules removed the temptation to deviate.

This article is for informational purposes only and does not constitute financial or tax advice.