The year's best-performing tech stock — AMD — got crushed

  • Chipmaker Advanced Micro Devices is the best-performing tech stock of the year, up 85 percent so far.
  • The stock slid with the rest of the tech sector Monday, falling as much as 11 percent before closing down 9.5 percent.
  • AMD competitor Nvidia also suffered a steep drop.
Lisa T. Su, CEO of Advance Micro Devices.
Adam Jeffery | CNBC
Lisa T. Su, CEO of Advance Micro Devices.

Advanced Micro Devices, the year's best-performing technology stock, got pummeled Monday as the entire tech sector took a nosedive.

Shares of AMD tumbled as much as 11 percent on Monday to a low of $18.80, the biggest decline among the 66 companies in the S&P 500 tech index. AMD closed down 9.5 percent, well below the Information Technology Index, which closed down 3.5 percent.

Despite the setback, AMD is still the top tech gainer of the year, rising more than 85 percent. The stock hit its peak on Sept. 13, when it traded at $34.14, and has since been on a downward spiral, dropping more than 40 percent.

AMD has benefited this year from market share gains in the computer chip market and rival Intel's struggles in delivering next-generation processors. AMD competes with Nvidia in the market for graphics chips used for gaming and cloud computing. Nvidia was the second-biggest decliner on Monday, dropping 7.8 percent.

Last month, AMD reported 4.4 percent revenue growth in the third quarter to $1.65 billion.The stock sank on a weaker-than-expected outlook for the fourth quarter.

WATCH: Cloud plays may be 'best tech stocks to own' as 2018 ends: Cramer