WASHINGTON (Reuters) - Inventories at wholesalers grew 0.4 percent in January, suggesting less of a boost to economic growth than expected.

The reading, reported on Friday by the Commerce Department, was below analysts' expectation of a 0.6 percent gain. The department said inventories grew 1.1 percent in December, slightly more than its previous estimate of 1.0 percent

Sales by wholesalers dropped 0.1 percent in January, confounding analysts who had forecast a 0.8 percent gain in a Reuters poll. The drop was the largest since a 0.3 percent decline in May and came after a robust 1.4 percent rise in December.

(Reporting by Doug Palmer, Editing by Andrea Ricci)