As of November 2026 Quest Diagnostics has a market cap of โน2.650 Trillion. This makes Quest Diagnostics the world's 862th most valuable company by market cap according to our data. The market capitalization, commonly called market cap, is the total market value of a publicly traded company's outstanding shares and is commonly used to measure how much a company is worth.
On Nov 8th, 2026 the market cap of Quest Diagnostics was reported to be: