My Costco price tracker is pretty stable, but big increases hit oil and protein

Prices have held steady at Costco in spite of a turbulent year — but cracks are starting to show.

Gary Hershorn/Getty Images Business Insider has been tracking 45 items at Costco to see how energy costs affect retail prices.

President Trump's conflict with Iran has disrupted oil and transportation markets around the world.

Most products have had minimal price changes, but some like motor oil and whey protein are way up.

Like the proverbial pot that's been watched but won't boil, the Costco prices I've tracked this year have remained remarkably calm amid an economy full of heat.

A basket of 45 items I'm following rose 3% since July, but that change is largely attributable to the recent surge in motor oil prices.

Overall, the numbers I see on my local warehouse shelves tell a very different story than what I would expect after following the tumultuous news from around the world.

Costco prides itself on keeping shelf prices in its warehouses close to wholesale prices for its members, which makes it a useful early read on supply-cost pressures.

It's hardly a national price index, but it does reveal how global economic forces are showing up in an ordinary US community like Madison, Wisconsin.

My data show that grocery and merchandise prices remain steady, with small hikes and discounts mostly balancing out in the total basket.

Meanwhile, some items like motor oil, protein powder, and aluminum foil are starting to show signs of pressure from their respective commodity markets.

Costco did not respond to a request to comment for this story.

On a conference call last month, CEO Ron Vachris said the company works with vendors to deal with commodity price increases and keep prices in check.

"It's a continual focus for all of our buyers in looking at how to reduce pricing," he said.