Just caught the latest Commerce Department data on U.S. business inventories, and there's an interesting edge to what's happening. Inventories barely budged in December, up just 0.1 percent after sitting flat the month before. Most analysts had predicted no change at all, so this is pretty much in line with expectations.

What caught my eye though is the switch in momentum when you look at sales versus inventory levels. Sales jumped 0.5 percent in December compared to 0.6 percent in November, while wholesale sales actually spiked 1.0 percent. Manufacturing sales moved up 0.5 percent too. Retail stayed unchanged, but the broader picture shows sales are outpacing inventory growth pretty significantly.

The inventory breakdown shows wholesale ticked up 0.2 percent, while both manufacturing and retail edged up 0.1 percent each. Here's the thing that stands out though: because sales are rising way faster than inventories are building, the inventory-to-sales ratio actually dipped to 1.36 from 1.37. It might seem like a small shift, but it suggests businesses are moving their stock faster than they're replenishing it. Worth keeping an eye on as we head into the next quarter.