Applied Materials' stock price slumped by double digits after the semiconductor equipment maker reported a project revenue decline amid tariff worries in China.

Beijing E-Town Semiconductor Technologies , a semiconductor equipment firm backed by Beijing's government, on Wednesday said it has sued U.S. chip equipment supplier Applied Materials over alleged trade secrets infringement.

Applied Materials (AMAT) stock falls after the company issued guidance that fell short of Wall Street's expectations. Warren Buffett's Berkshire Hathaway (BRK-B, BRK-A) added to its stakes in homebuilder stocks Lennar (LEN) and DR Horton (DHI).

Applied Materials ( NASDAQ: AMAT) provided fourth quarter fiscal 2025 guidance that demonstrated a year-over-year revenue decline of 4.9% and an adjusted earnings per share drop of 9% during its latest financial results on Thursday.

Shares of technology companies declined as a tepid outlook from one major chip-equipment manufacturer cast a pall on the semiconductor sub-sector. Shares of Applied Materials plunged after the maker of semiconductor manufacturing equipment forecast growth short of Wall Street expectations.

CNBC's Kristina Partisinevelos joins 'Squawk on the Street' to discuss the latest earnings from Applied Materials.

Applied Materials reported third-quarter revenue of $7.3 billion, beating analyst estimates of $7.22 billion. The chip equipment manufacturer reported third-quarter adjusted earnings of $2.48 per share, beating analyst estimates of $2.36 per share, according to Benzinga Pro.

The Chinese company allege Applied Materials Inc. illegally obtained, used and revealed its core technologies related to the application of plasma source in treating the surface of wafers.