EIA cut Henry Hub's 2027 forecast 41 cents in a month. The Haynesville cost stack will tell whether the revision overshot.

EIA's May 2026 STEO lowered the Henry Hub 2027 forecast to $3.18 — a 41-cent cut from the April STEO's $3.59 in a single month. The same STEO has US dry gas production reaching record highs, with Haynesville projected to add about 1.6 Bcf/d in 2027 and remain one of the largest contributors to dry-gas growth. The price forecast just moved sharply lower; the production-growth forecast didn't. The Haynesville cost stack is what reconciles them.

Haynesville is the structural marginal producer at Henry Hub. Appalachian growth remains takeaway-constrained. Permian gas is associated with oil — +0.6 Bcf/d in 2027 by GOR creep, less price-responsive than dry-gas basins. Haynesville is dry, Gulf-Coast adjacent at near-zero basis, and rig-responsive within two-to-three quarters of an HH signal. The Haynesville cost curve is the HH cost curve at the margin.

Legacy Haynesville top-tier wells clear in the low-$3s on half-cycle math. Western Haynesville (Robertson, Leon, and Freestone counties) top-tier wells clear at $2.70–$3.10/Mcf per Rystad and operator disclosures, with current D&C costs near $31 million per well — down 21% from $35 million. On a PV20 basis at the operator-stated $25 million D&C target, Western Haynesville needs about $3.67/Mcf. The geology is why the gap exists: 17,000-foot-plus TVDs, pressures near 17,000 psi, bottom-hole temperatures touching 450°F.

The DUC tailwind buys time, but not much. East Daley reported 149 DUCs across five major Haynesville producers in April 2026; at current drawdown rates that buffer could thin materially by late 2026 into 2027. After that, growth has to come from new rigs and completions priced against the steeper end of the curve.

A $3.18 strip does not obviously fund a broad push into Western Haynesville drilling once the DUC buffer is gone. If Haynesville must supply a growing share of incremental dry gas after the buffer fades, the structural floor could migrate toward the mid-$3s by late 2027.

When the DUC drawdown ends and the rigs have to clear, the strip moves. Or the production forecast does.