As of December 2025 Quest Diagnostics has a market cap of โฌ17.52 Billion. This makes Quest Diagnostics the world's 1095th 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 Dec 6th, 2025 the market cap of Quest Diagnostics was reported to be: