Southbound molecules: Mexico's LNG buildout as Henry Hub's off-balance-sheet corridor.

U.S. gas exports run through three LNG corridors now, not one. The Gulf Coast complex shows up on the EIA chart. The cross-border pipes feeding Mexican LNG terminals don't — those molecules leave as pipeline exports and reappear as someone else's LNG in Asia.

The scale is small today and strategic tomorrow. Mid-2026 Mexican LNG capacity approaches 0.6 Bcf/d as both projects ramp — Altamira Fast LNG online with up to ~0.2 Bcf/d nameplate, plus Energía Costa Azul Phase 1 entering commercial ramp this spring. Against U.S. LNG capacity moving from roughly 17 Bcf/d toward the low-20s by end-2027, that's a rounding error. Don't read it as a second Sabine. Read it as a corridor whose growth depends on the FID stack behind it.

The physical paths are already wired. Sur de Texas–Tuxpan (2.6 Bcf/d, 2019) feeds Altamira on the Gulf side. North Baja Xpress plus Gasoducto Rosarito feed ECA on the Pacific side. Saguaro Connector — 2.8 Bcf/d from Waha to the Sonora coast, FERC-approved 2024, awaiting Mexico Pacific LNG FID — is the binary that turns the corridor structural. Mexico Pacific's offtake stack already books capacity to Shell, ExxonMobil, ConocoPhillips, Woodside, POSCO, and Zhejiang Energy. The contracts are in. The pipe is permitted. What's missing is the FID.

The structural premium is geographic. Pacific Mexican terminals (ECA, Mexico Pacific) skip the Panama Canal — saving roughly $0.50–1.00/MMBtu of shipping and transit risk on every cargo to Asia. That makes Waha-sourced feedgas via Saguaro the lowest-cost laid-in Asian LNG in the world on paper. On simple netback math: at JKM near $9–10, the implied Waha floor through that corridor sits in the $5–6 range — against current sub-zero day-ahead prints. The arbitrage is the entire point.

Sheinbaum's administration sends mixed signals — state support for the Sonora corridor, ongoing permitting risk. The Saguaro CEO change and the DOE deadline extension to 2032 sit on the slip side. Through 2027, the corridor stays sub-1 Bcf/d. Past that, the FID decides.

U.S. LNG export forecasts capture the molecules going through Gulf Coast terminals. They miss the ones going through Mexico. The molecules don't care which flag they fly under.