Shares of Google-owner Alphabet crossed the $1,000 threshold on Monday, but failed to prevent a fall for Wall Street after several days of gains.
Selected tech stocks, energy firms and financial companies also escaped the decline, but a fall in Apple weighed on markets
The tech-heavy Nasdaq closed down 0.16% to 6,295.68.
Apple is hosting its annual developer conference, where it showcases new software. High expectations drove the firm's share price up at the end of last week, but on Monday the stock closed down 1%.
The firm's tech rivals fared better.
Microsoft closed the day up 0.72%, while Amazon and Alphabet cemented their position in the elite league of firms with shares worth more than $1,000.
Alphabet closed up 0.78% at 1,003.88 while Amazon gained 0.46% to 1,011.34.
Financial firms, including Visa and American Express, traded higher in advance of next week's Federal Reserve meeting. The US central bank is expected to increase interest rates, which would benefit those firms.
After sliding last week, ExxonMobil and other energy companies regained ground amid uncertainty over how a dispute between Qatar and other Gulf states might affect oil production.