Inventories at U.S. wholesalers jumped ahead of Wall Street expectations in May, boosted by growth in durable goods stocks, while sales at the wholesale level increased at a milder pace, a government report on Friday showed.

The Commerce Department (search) said wholesale inventories rose 1.2 percent in May after an upwardly revised 0.2 percent gain in April. Analysts had expected a 0.5 percent rise in May wholesale inventories, according to a Reuters survey.

Sales grew at a slightly weaker pace, rising 0.5 percent in May compared to 0.9 percent in April.

April inventories were originally reported as a 0.1 percent decline, while April wholesale sales had been initially reported showing a 0.8 percent gain.

The gain in inventories and slower sales propped up the inventory-to-sales ratio (search), which measures how long it would take to draw down stocks at the current sales pace, to 1.13 months' supply from 1.12 in April.

Inventories of durable goods -- items meant to least three years or more -- rose 1.5 percent in May, reflecting large rises in metals, hardware and lumber stocks. The durable goods increase was the highest since a matching 1.5 percent rise in November 1999.

Non-durable goods inventories rose 0.6 percent, with a 3.4 percent drop in farm products providing a slight drag.

Financial markets, which rarely respond to the wholesale inventories and sales data, showed no reaction.

Earlier this month, Commerce said factory inventories climbed 0.5 percent in May. Retail sector inventories will be announced in business inventories figures due to be released next week.