WASHINGTON U.S. consumer confidence slipped in May as concerns about the economic outlook lingered, but more households planned to purchase motor vehicles and other big-ticket items over the next six months, which could support consumer spending.

The Conference Board said its consumer confidence index slipped to 102.3 this month from an upwardly revised 103.7 in April. Economists polled by Reuters had expected the index to fall to 99 from the previously reported reading of 101.3.

"While consumer confidence has fallen across all age and income categories over the past three months, May's decline reflects a particularly notable worsening in the outlook among consumers over 55 years of age," said Ataman Ozyildirim, senior director, Economics at The Conference Board.

"Plans to purchase autos and big-ticket appliances ticked up somewhat compared to April."

Consumers' 12-month inflation expectations dipped to 6.1% from 6.2% last month.

(Reporting by Lucia Mutikani; Editing by Chizu Nomiyama)