coopMarketShare = min(1, elapsed × 1%) corpMult = max(0, 1 − coopMarketShare × 2)

Every year, 1% of the population joins a Sharphill community. Each new resident stops spending at conventional businesses (direct customer loss) and their local co-op starts competing with those businesses for everyone else (competitive pressure). The combined effect is 2% annual erosion of corporate market share. Corporations start at 100% and reach 0% at year 50. corpMult is the key multiplier — it scales all corporate profit and wealth returns throughout the model.

Years 0–8: strength = 0.20 (grace period — infrastructure being built) Years 8–28: t = (elapsed − 8) / 20 strength = 0.20 + 0.80 × t² Year 28+: strength = 1.00 (full capacity)

Co-op member returns do not flow at full strength immediately — the physical and organisational infrastructure takes time. The first 8 years are a grace period (20% capacity). From year 8 to 28, capacity ramps up quadratically (slowly at first, then accelerating). After year 28, the co-op economy runs at full power. The quadratic ramp reflects real-world cooperative dynamics: the hardest part is the beginning.

maxAdoption = 1% × 50 years = 50%displacement = (coopMarketShare / maxAdoption)² incomeGrowthRate = +4% / yr − displacement × 12%incomeGrowthRate = max(−2.5%, incomeGrowthRate)

The top 5% — owners, investors, landlords — start with +4% / yr income growth (rents, dividends, business profits). As co-ops grow, this slows. The effect is quadratic: small and barely noticeable early on, then compounding sharply in the second half. At 25% co-op adoption (halfway to maximum), growth is already cut by 3 percentage points. By 50% adoption, growth hits the floor of −2.5%/yr. This mirrors how corporate income erosion actually works: landlords and investors can absorb early competition, but the pressure is relentless and accelerating.

taxReductionFactor = 45% × (elapsed / 50) effectiveTaxRate = originalTaxRate × (1 − taxReductionFactor)

In a Sharphill community, the cost of government shrinks steadily. People stress less, need fewer hospitals and police, live locally and need less highway infrastructure, and the poorest are housed and fed by the co-op economy rather than by the state. By year 50, everyone's effective tax rate is 45% lower than today's baseline. The reduction is linear — a small saving every year that compounds into a meaningful increase in take-home income. This applies to all groups equally.

spendShare[category] = baseline[category] × categoryMult × (1 + drift × elapsed) Top 5% drift: +0.3%/yr — costs rise (selective services, premium market) Residents drift: −0.2%/yr — costs fall (local economy matures) Housing (residents): 0% — override; co-op ownership means no rent Food multiplier: 50% of baseline — local/bulk production halves food costs

Spending shares shift gradually over time. For the top 5%, as mainstream services become more premium (fewer people competing for the same luxury market), their relative costs drift upward. For Sharphill residents, the local co-op economy becomes more efficient over time — food, transport, and retail all get proportionally cheaper. Housing costs are eliminated entirely through co-op ownership (no landlords). These drifts accumulate each year: a small change annually, a large structural difference by year 50.

totalRev = Σ(income_group × spendingShare_group) ← all groups' spending totalTaxPop = Σ(income_group × effectiveTaxRate_group) coopEconomyTax = totalRev × coopMarketShare × 22%welfarePool = (totalTaxPop + coopEconomyTax) × welfareReturn salaryPool = totalRev × salaryRate ← grows 68% → 85% over 50 years

All groups' consumer spending creates total revenue, which then gets split. The welfare pool is funded by income taxes — it redistributes money to all groups proportional to their welfare shares. Importantly, the co-op economy pays its own corporate-equivalent tax (22% of co-op revenue), which flows into the welfare pool alongside regular income tax — so the welfare pool is stabilised even as conventional tax revenue changes. The salary pool represents wages paid to workers out of total revenue; as the co-op economy matures, co-ops pay a larger share of revenue as wages (up from 68% to 85%).

fullProfit = Σ(sectorRevenue × profitMargin) ← what profit would be at 100% corporate profit = fullProfit × corpMult ← actual corporate profit (shrinks to 0) coopCapitalTransfer = (fullProfit − profit) × coopMarketShare × strength

Sectors generate profit as a fraction of their revenue. In the current system all of it goes to corporate owners. In Sharphill, only the corporate-controlled portion generates corporate profit — and that shrinks to zero as corpMult falls. The rest, the profit from co-op-controlled revenue, is the co-op capital transfer: money that used to go to shareholders now belongs to co-op members. This is the core of the user's insight: as top 5% purchasing power falls, that value does not disappear — it flows directly to residents. At year 50 with corporations at 0%, the entire sector profit passes through the co-op to residents.

Top 5% grossIncome = baseIncome + welfarePool × 5% ← small welfare share + salaryPool × 8% ← salary/dividend income + profit × topProfitShare × 55% ← corporate profit (scales with corpMult) + wealth × 4% × corpMult ← investment returns (shrinks with corpMult) topProfitShare = 10% × corpMult ← starts at 10%, falls to 0% Middle-class & welfare residents grossIncome = baseIncome + welfarePool × welfareShare ← 12% working, 83% welfare + salaryPool × salaryShare ← 15% working, 2% welfare + profit × coopEquityShare ← corporate equity (shrinks) + coopMemberPool × 50% ← co-op member dividend (grows) + coopCapitalTransfer × 50% ← co-op profit transfer (grows) coopEquityShare = coopMarketShare ← equity in corporate sector coopMemberPool = totalRev × coopMarketShare × 16% × strength

The top 5% benefit from corporate profit and investment returns — both of which scale with corpMult and decline toward zero. Their wealth still compounds but only on the corporate portion. Residents benefit from two co-op income streams that grow as the co-op economy does: member dividends (16% of co-op revenue, like a patronage rebate) and the capital transfer (former corporate profit now owned by members). The transition is smooth: as corporate equity income shrinks, co-op income grows to replace it and then exceed it.

spending = grossIncome × spendingRate tax = baseIncome × effectiveTaxRate disposable = grossIncome − spending − tax monthlyPurchasingPower = disposable ÷ 12

This is the number shown in the simulator. Purchasing power is the monthly disposable income after all essential spending categories (housing, food, transport, retail) and income tax are deducted from gross income. Note that tax is applied only to base income — additional co-op flows and welfare redistribution are not taxed again. Wealth is updated each year: wealth × (1 + wealthCompound) + disposable. For the top 5% in Sharphill, wealth compounding is also scaled by corpMult, reflecting the erosion of their asset base.

annualContribution = totalRev × coopMarketShare × 5%globalCumulative = Σ annualContribution × cityPopulation (4,000,000,000 people)

5% of all co-op sector revenue is channelled into the Commonwealth Impact Fund — a global pool for large-scale projects that individuals or single cities cannot finance alone: climate reversal, space exploration, shared infrastructure. As the co-op economy grows from 0% to 50% of market share, this fund grows proportionally. The global cumulative total extrapolates the per-person figure to a world-scale estimate using a city population of 4.0 billion.

profitToTop1 = 38% ← 4x higher than Sharphill (no co-op sharing) welfareReturn = 58% ← less tax recycled as welfare salaryRate = 52% ← lower wage share of revenue subsidyGrowth = +0.3% / yr ← corporate subsidies grow each year Spending drift (current): Top 5%: -0.2% / yr (costs fall — luxury market grows efficient) Middle-class: +0.1% / yr (costs slowly rise) Welfare: +0.3% / yr (costs rise fastest — squeezed bottom) Income growth (current): Top 5%: +2.6% / yr Middle-class: +0.9% / yr Welfare: -0.6% / yr (income falls in real terms)

No cooperative displacement, no tax reduction, no capital transfer to residents. Corporate profits grow unimpeded and flow predominantly to top owners. Spending drifts penalise lower-income groups (housing inflation, rising essentials) while the top 5% benefit from increasingly efficient luxury services. These parameters are calibrated against published OECD and BLS data.