The Caustic Soda Index Skipped July
Thursday's PPI took 2.2% off alkalies and chlorine, the sharpest one-month drop in that series since January 2024. The sub-index that would tell you whether caustic caused it is the one BLS did not publish. Nine days earlier, Westlake guided the second half higher.
The BLS producer price file for chemicals carried 219 live series into July. On Thursday morning, when the July numbers landed, 215 of them got a new row.
Sodium hydroxide did not.
The caustic soda index, WPU061303024, last printed in June at 157.928. Its parent printed. Its sibling printed.
Shaving preparations and prescription respiratory preparations were the only other chemical series in the file that came up empty, which tells you roughly how much company caustic soda has in that gap.
On a quiet month that is a filing curiosity. July was not a quiet month.
The one inorganic line that fell
Alkalies and chlorine, WPU061303, came in at 423.377, down 2.21% from June. Run every month-over-month change in that series back to 1973 and the most recent drop that large is January 2024.
Everything around it went up. Inorganic chemicals other than alkalies and chlorine rose 0.51%, potassium and sodium compounds 0.73%.
So the whole inorganic complex was firm in July except the chlor-alkali line, which gave back most of a five-month run: 409.866 in January, 432.956 in June, and now sitting 3.3% above January and 0.24% above July of last year (chart below).
The accented line is the one that ran hardest into the break. Caustic soda was up 10.3% January to June against 2.4% for the other published member of its group, so the 2026 run in alkalies was substantially a caustic run.
And then it stopped reporting.
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