WASHINGTON U.S. wholesale inventories were unchanged in May after declining for two straight months, suggesting inventory investment could support economic growth in the second quarter.

The Commerce Department said on Monday that wholesale inventories were unchanged instead of dipping 0.1% as previously reported last month. Stocks at wholesalers fell 0.3% in April.

Economists polled by Reuters had expected that inventories would be unrevised. Inventories are a key part of gross domestic product. They increased 3.7% on a year-on-year basis in May.

Private inventory investment rose at its slowest pace in 1-1/2 years in the first quarter, helping to restrict GDP growth to a 2.0% annualized pace in that three-month period.

The careful inventory management amid expectations of weaker demand because of higher borrowing costs is weighing on production at factories.

Wholesale motor vehicle inventories increased 1.1% in May after rising 0.3% in April. But inventories of furniture continued to decline as did stocks of lumber, paper, apparel, farm products and petroleum.

Excluding autos, wholesale inventories slipped 0.1% in May. This component goes into the calculation of GDP.

Sales at wholesalers fell 0.2% after being unchanged in April. At May's sales pace it would take wholesalers 1.41 months to clear shelves, up from 1.40 in April.

(Reporting by Lucia Mutikani; Editing by Andrea Ricci)