Import Prices YoY

Import Prices YoY is the 12-month percent change in the US Import Price Index, part of the Import and Export Price Indexes (MXPI). The program is run by the Bureau of Labor Statistics International Price Program (IPP), which combines business surveys with trade records. It measures average price change for nearly all merchandise imports plus air passenger fares and air freight.

It reflects inflation felt by importers. It does not measure price levels or domestic consumer inflation, and import duties are excluded.

Prices are collected each month to reflect the trade month. Business surveys price deals near the first day, and trade records cover the full month. BLS publishes results each month about 2 weeks after the measured month. Publication is embargoed until 8:30 AM Eastern Time, though funding lapses can delay it.

Each release also shows export prices, locality of origin splits, terms of trade, and tables of index values and percent changes. Data are revised in each of the 3 months after first release. Weights update each January on a 2-year lag. A rise signals imported inflation with pass-through to domestic production, and the 12-month percent change is the preferred read without seasonal adjustment.

The all-goods index blends 5 end-use groups, each weighted by its share of imports.

• Foods, feeds, and beverages, 7.220%: agricultural foods, feeds and beverages plus fish and distilled beverages.
• Industrial supplies and materials, 24.921%: fuels such as petroleum and natural gas plus chemicals, metals, and building inputs.
• Capital goods, 27.715%: machinery and equipment such as electric generating equipment, nonelectrical machines, and transportation equipment excluding motor vehicles.
• Automotive vehicles, parts, and engines, 12.858%: finished vehicles plus parts and engines.
• Consumer goods excluding automotives, 27.286%: manufactured durables, manufactured nondurables, and nonmanufactured items.

The September 2023 release published October 13, 2023 gives a clear example. All-import prices rose 0.1% on the month after 0.6% in August and 0.9% in the third quarter, but fell 1.7% from 12 months earlier. Fuel jumped 4.4% on the month while nonfuel fell 0.2%, and fuel stood 8.9% lower than 12 months earlier.

Inside fuel, petroleum rose 4.9% on the month but stood 6.6% lower than 12 months earlier. Natural gas fell 7.8% on the month and 53.8% over 12 months, showing why the 12-month read smooths volatility.

1. Modified Laspeyres index: The index uses a Lowe formula with fixed trade-dollar weights, updated each January on a 2-year lag. Each month derives from the prior month as a chained index.
2. Base period: Series use 2000=100 where possible, with values rounded to a tenth before percent changes. YoY equals present index over year-ago index minus 1, times 100.
3. Seasonal adjustment: No index is seasonally adjusted, so the 12-month change is the preferred read.
4. Cell-mean imputation: A missing price is first filled with the parent-group move. It is replaced with a midpoint interpolated value when the next true price arrives.
5. Quality adjustment: A quality-adjusted link price strips the value of specification changes. Computers use hedonic regression, and other changed items are substituted.
6. Toy example: With weights 70 and 30 and a prior index of 107.0, a link ratio of 1.036 lifts the index to 110.9. That is a 3.6% monthly gain. Yet YoY can still read minus 1.4% if the year-ago index was 112.5.