Businesses increased their inventories of goods 0.9 percent from the prior month to a seasonally adjusted $2.71 trillion, the Commerce Department said Thursday, a sign of confidence that the U.S. economy will continue to grow and households will keep spending.

This was the biggest monthly gain in four years. February inventories were revised to show a 0.4 percent increase. Inventories were up 2.0 percent from a year earlier.

The inventory build came alongside a larger gain in sales. The combined value of manufacturers’ shipments and trade sales rose 2.1 percent in March to $2.06 trillion and was up 7.1 percent from a year earlier.

That combination pushed the inventory-to-sales ratio down to 1.32 from 1.33 in February and 1.38 in March 2025. The decline indicates that inventories became leaner relative to sales even as companies added to stockpiles.

Inventory accumulation is closely watched because private inventories are a component of gross domestic product. Rising inventories can add to economic growth, particularly when they reflect businesses preparing for future demand rather than being left with unsold goods.

The March report showed inventory increases across all three major business categories.

Manufacturers’ inventories rose 0.6 percent in March to $956.3 billion, while shipments rose 1.4 percent. Compared with a year earlier, manufacturers’ inventories were up 1.3 percent and shipments were up 5.5 percent. The manufacturing inventory-to-sales ratio fell to 1.51, down from 1.57 a year earlier.

Retail inventories rose 0.6 percent to $820.6 billion, while retail sales rose 1.9 percent. Retail inventories were up 1.9 percent from a year earlier, while sales rose 4.4 percent. The retail inventory-to-sales ratio slipped to 1.26 from 1.29 a year earlier.

Motor vehicle and parts dealers accounted for a notable share of the retail inventory increase. Their inventories rose 1.2 percent in March and were up 2.7 percent from a year earlier. Their inventory-to-sales ratio climbed to 1.88, compared with 1.80 a year earlier.

Wholesalers posted the largest monthly inventory gain among the major groups. Wholesalers’ inventories rose 1.3 percent to $932.8 billion, while sales jumped 2.8 percent. From a year earlier, wholesaler inventories were up 2.9 percent, while sales were up 10.9 percent. The wholesale inventory-to-sales ratio fell to 1.21 from 1.30 in March 2025.

The data suggest businesses continued to rebuild inventories in March without accumulating excess stock relative to sales. In a weaker economy, inventories often rise because demand disappoints. In March, inventories rose while sales accelerated.

The figures are adjusted for seasonal and trading-day differences but are not adjusted for price changes. Through March,