Statutory tax laws frequently contain discontinuous step-functions ('cliffs') where a single dollar of additional consideration or estate valuation triggers tens or hundreds of thousands of dollars in retroactive tax liability. Below, we open-source four deterministic Vanilla JS calculators and Retina 2x editorial charts from the EastCorp Capital Quantitative Tax & Real Estate Desk covering New York's 105% estate cliff, Delaware's Assumed Par Value corporate recalculation, the Hamptons $2.0M Peconic Bay CPF cliff, and IRS Form 8606 Backdoor Roth pro-rata aggregation.

1. New York $7.16M Estate Tax '105% Cliff' (N.Y. Tax Law § 952(c)) & Conditional Santa Clause

2026 NY $7.16M Estate Tax 105% Marginal Cliff & Santa Clause Matrix

Between $7,160,000 and $7,518,000 (105% of the basic exclusion), New York State phases out 100% of the unified estate tax credit—generating an effective marginal tax rate exceeding 190% to 229%. A conditional charitable bequest ('Santa Clause') donates the excess above $7.16M to a 501(c)(3) charity whenever the tax saved exceeds the gift.

2. Delaware C-Corp Assumed Par Value Franchise Tax (8 Del. C. § 503(a)(2)) & NY LLC § 206 Albany Route

2026 Delaware Franchise Tax & NY LLC § 206 Albany Arbitrage Matrix

3. Hamptons 2.0% Peconic Bay CPF ($2.0M Cliff) & Philadelphia 4.278% Realty Transfer Tax

2026 Northeast Conveyance Desk: Hamptons 2% CPF & PA/Philly Transfer Tax

4. IRS Form 8606 Backdoor Roth Pro-Rata Aggregation (IRC § 408(d)(2)) & 2026 RMD Table III

2026 Retirement Tax Desk: Form 8606 Backdoor Roth & RMD Table III

5. Live Interactive Sandbox Widgets (JSFiddle DR 89)

Test the statutory calculation engines directly in the browser or fork the implementation: