Monthly net income vs. monthly spending (€) — projected across career phases
End of 2026
€17,400
12 mo × €1,450
End of 2027
€44,100
+€26,700 Senior yr
End of 2028
€111,300
+€67,200 Quant yr 1
End of 2030
€245,700
+€134,400 Quant yr 2–3
Cumulative savings (€) — quarterly, 2026–2030
A disciplined dollar-cost averaging strategy into the Vanguard S&P 500 (VOO / VUSA), scaling monthly contributions with each career phase. Three return scenarios — bear (5% p.a.), base (10% p.a.), and bull (15% p.a.) — projected from SWE II through five years post-Quant transition, totalling a 12-year window.
SWE II — 2026
€500 / mo
€6,000 / year invested
34% of monthly savings
Senior SWE — 2027
€1,200 / mo
€14,400 / year invested
57% of monthly savings
Quant Dev — 2028–2032
€3,500 / mo
€42,000 / year invested
62% of monthly savings
Post-Quant — 2033–2037
€3,500 / mo
Maintained — compounding
Portfolio accelerating
ETF portfolio value (€) — Vanguard S&P 500, 3 return scenarios, Q1 2026 – Q4 2037
Base — 10% p.a. (S&P 500 historical avg)
@2027 — pre-quant
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Base case (10% p.a.)
@2030 — quant yr 3
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Base case (10% p.a.)
@2032 — quant yr 5
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Base case (10% p.a.)
@2037 — quant yr 5+
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Base case (10% p.a.)
Key assumptions
ETF: Vanguard S&P 500 — VOO (USD) or VUSA (EUR-listed). Broad US market exposure, 500 companies. TER ~0.07%.
Strategy: Dollar-Cost Averaging — Fixed monthly contributions regardless of market conditions. Eliminates entry-timing risk.
Base case: 10% p.a. — S&P 500 long-run nominal average (1928–2024). Dividends reinvested (accumulating share class).
Bear case: 5% p.a. — Below-average decade, elevated inflation, or a prolonged drawdown / slow recovery scenario.
Bull case: 15% p.a. — Sustained tech / AI-driven expansion. Historically rare but not unprecedented over multi-year runs.
Tax & FX: Dutch box 3 wealth tax and EUR/USD exposure not modelled. Actual net returns will differ. Consult a tax advisor.
The baseline plan is solid. These are the highest-ROI levers that are currently untapped. Each is independently actionable and compounds with the others. Deltas are estimated against the baseline wealth position by age 37 (end of 2037).
Timeline
Pull quant transition forward 6–12 months
C++ + DSA prep can run in parallel with the WBD day job from today — not after the Senior promotion. Aggressive evenings/weekends from mid-2026 realistically moves the quant hire to late 2027 instead of mid-2028.
+€50k–€90k by 37
6–12 extra months of €5,600/mo savings + ETF compounding at the highest contribution rate.
Tax & Location
Relocate at the quant transition (Zurich / Singapore)
Netherlands effective tax above ~€70k gross is 49.5%. The identical Optiver / IMC role in Zurich (20–22% effective) or Singapore (~15%) yields €11k–€13k net/month vs. €8,500 in Amsterdam. This is the single highest-ROI lever.
+€200k–€350k by 37
€2,500–€4,500/mo extra net income × 9 years, fully reinvested. Dwarfs any ETF or savings-rate optimisation.
Negotiation
Price the quant offer aggressively
€75k signing/bonus over 2 years is the floor, not the ceiling. Competitive HFT firms (Optiver, IMC, Jane Street) regularly offer €100k–200k for strong candidates. A competing offer from two firms forces them higher. Never accept the first number.
+€25k–€125k one-time
Lump sum invested at the start of Quant Year 1 compounds to €40k–€200k by 37 depending on returns.
Housing
Buy rather than rent at Senior SWE income
At €90k–€95k gross you qualify for a €350k–450k mortgage in NL. Hypotheekrenteaftrek (mortgage interest deduction) reduces the effective rate. Equity builds in parallel with savings; the property becomes a wealth vehicle instead of a monthly cost drain.
Equity + tax relief vs. renting
Amsterdam property returned ~4–6% p.a. historically. Even modest appreciation on €400k = €16k–€24k/yr wealth gain not in any current projection.
Tax wrapper
NL lijfrente pension contributions
Personal pension contributions are fully deductible at your marginal rate (49.5% at Senior SWE+). Investing €6k–10k/year into a lijfrente wrapper saves €3k–5k in income tax annually — money that would otherwise disappear — while the portfolio inside grows free of box 3 wealth tax.
+€27k–€45k tax saved by 37
~€3k–€5k/yr tax saving × ~9 yrs = €27k–€45k recaptured, plus the compounding inside the wrapper.
Side income
Freelance consulting during prep phase (2027–2028)
10–15 hrs/week freelance software consulting at €100–€150/hr adds €4k–€6k/month with minimal career risk. The prep phase is a full year where Senior SWE salary is the ceiling — side income closes that gap directly.
+€48k–€72k over 12 months
Invested into ETF at the exact ramp-up moment. By 37, this cohort of capital has 10 years to compound.
Cumulative wealth by 37 — baseline vs. optimised scenarios (€), quarterly 2026–2037
Optimised — earlier quant + freelance + pension
Best case — above + relocation + aggressive bonus
Baseline by 37
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Current plan, NL-based
Optimised by 37
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Earlier quant + freelance + pension
Best case by 37
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All levers + relocation
Best case uplift
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vs. baseline at 37
The current situation appears financially healthy rather than fragile. The present challenge is temporary single-income pressure, not insufficient earning potential.
— Financial Growth & Career Projection Plan, May 2026