Shares in internet search engine Google have breached the $500 mark.
They hit records of $510 during trading on the Nasdaq stock market, before closing $14.60 higher at $509.65.
Google shares have been boosted by strong growth, and expectations that the firm will continue to capitalise on the online advertising market.
It has also benefited from problems at its closest rival, Yahoo, which has suffered from a downturn in financial and car advertising in recent months.
Last month, Yahoo said quarterly profits had fallen 38% to $158m on the back of weak advertising revenues.
As a result analysts have been questioning Yahoo's long-term strategy, fearing that it is less nimble than some of its rivals.