The Execution-Certainty Wedge: Allocation, Distribution, and the Design of Housing-Market Instruments

Completion advantages can change who acquires housing without materially changing total realised value. This paper compares a per-entity acquisition cap, a contention-linked fair share, and a contention-triggered duty in a stylised agent-based housing market. A fixed-offer theoretical result characterises how proportional charges select acquisitions by their relative effective-offer margins. The resulting allocative and welfare trade-offs are evaluated numerically across access targets and distributional weights. Key Findings:1. Trade-offs between Access and Value: At the baseline, a per-entity cap reduces unserved owner-occupier exits from 41.9% to 8.7% at an 11.3% loss in aggregate realised valuation. A contention duty reduces exits to 36.6% with aggregate valuation changes near zero.2. Target-Dependent Instrument Rankings: Under a common access target (evaluated across 16 independent validation seeds), the fair-share rule preserves more aggregate value than the duty near a 10-percentage-point access gain, while the duty leads near 5 percentage points. 3. Institutional and Statutory Feasibility: Entity splitting neutralises static caps absent beneficial-ownership aggregation, while elastic listings under full seller incidence increase the allocative costs of all constrained regimes.4. Empirical Demarcation: Financing-associated price gaps from companion New York City administrative data document substantial heterogeneity across property types (9.3% in houses, 0.7% in condominiums, -1.2% in co-ops), but do not identify an excess over real completion costs sufficient to establish an empirical efficiency case for corrective duties. Replication and Release Notes (Version 3.1):Version 3.1 provides substantive methodological corrections, updated common-access target evaluations, and a fully verified, clean-environment replication package. For the itemized changelog, theoretical corrections, and reproduction audit, please refer to the included REVISION_NOTES.md. Companion Empirical Study:Loschi, Pablo, Who Gets the House? Financing-Associated Price Gaps in New York City (September 6, 2026), SSRN: https://ssrn.com/abstract=7421138, DOI: 10.2139/ssrn.7421138. Replication Archive: https://doi.org/10.5281/zenodo.22421850.