The surge in the U.S. producer-price index could be a head-fake on inflation.

Some analysts said the unexpectedly hot producer-price index could be an indication that inflation is picking up steam. But beneath the headline numbers there are reasons to doubt that the index is signaling inflation.

Absent the volatile food and energy categories, prices of goods did not rise at all in October. And prices of many household goods, from appliances to toilet paper, actually fell.

The rise in the index was driven by the services category. But this doesn’t mean the price of services went up because a big part of the gain was in a little-understood category called “trade services,” the part of the index keyed around wholesale distributors and retailers.

Trade services was one of the biggest gainers in the services category for October. Unlike the other categories in the producer price index, which measure changes in prices received by establishments for the sale of goods produced or services provided, the gauge for the trade services sector measures the margins received by retailers and wholesalers.

This means that a rise in trade services components of the index does not necessarily indicate rising prices. If shops selling a can of soup for $1.00 paid 90 cents for soup in September and 89 cents in October, the retailer’s margin will have grown from 10 cents to 11 cents. Since trade services is a measure of margin changes, this would show up as a 10 percent gain–even though the relevant price fell.

Retail trade services, the margin for stores selling directly to consumers, rose 2.8 percent in October compared with the prior month. For the year, this gauge is up 1.0 percent. Wholesale trade services, the margin for distributors who sell products to the consumer-facing retailers, was up 1.4 percent for the month and was up 3.0 percent compared to a year ago.

The other big mover in the services category was advertising. Prices for ads were up 3.6 percent for October, which may reflect the high levels of spending by Republicans and Democrats in the midterm elections. Compared with a year ago, however, this category was flat.

Insurance companies’ prices rose 1.8 percent and are up 8.4 percent compared with a year ago. Transportation services rose 0.9 percent, which likely reflects shipping companies passing on some of their rising costs due to rising wages for truckers. Compared with the year ago, this category is up 5.5 percent.

Prices for “accommodation services,” meaning hotels and motels, were up 3.6 percent for the month. For the year, these were up 4.1 percent.

Software publishers got a boost, with their prices rising 0.8 percent in October. Software prices, however, have lagged prices across the broader economy. For the year, they are up just 0.4 percent.

Most other services prices were unchanged or down for the month.

Next week, when the government releases data on consumer prices, we will see definitively whether or not the hot producer-price index was a forewarning about inflation or just a sign that retailers and wholesalers had a good month,