The value of US tech stocks fell in August, and Eli Lilly (LLY.US) and Berkshire (BRK.A.US) performed well.

Major tech stocks saw their valuations shrink in August as concerns about rising costs of AI infrastructure and increased risk of an economic downturn made them particularly vulnerable during the market pullback.

Alphabet's (GOOGL.US) market value fell 4.7% last month amid concerns over its earnings, as YouTube advertising sales slowed, and a US judge's ruling against Google for antitrust violations and the emergence of new competitors such as OpenAI, which is developing an AI-based search engine prototype, also weighed on the company's shares.

Amazon's (AMZN.US) market value dropped 4.5% as online sales slowed.

Tesla's (TSLA.US) market value fell 7.7% last month after its second-quarter earnings disappointed and amid concerns over a new 100% tariff on Chinese-made electric vehicles in Canada, which the global carmaker began exporting from Shanghai last year.

Nvidia (NVDA.US), which accounts for more than 80% of the AI chip market, saw its market value drop 7.7% to $2.92 trillion in the last week of August after the company forecast third-quarter gross margins below market expectations and revenue only meeting expectations, disappointing investors who were expecting stronger results.

On the positive side, Eli Lilly (LLY.US) saw its market value soar nearly 20% to become the biggest gainer on the market, as the company's sales were strong and its new weight-loss drug significantly reduced the risk of type 2 diabetes in overweight adults.

Berkshire Hathaway (BRK.A.US) is seen by many as a proxy for the US economy. Its market value topped $1 trillion for the first time at the end of August, reflecting investor confidence in the conglomerate that Warren Buffett has spent nearly six decades building.

Meta's (META.US) market value also rose nearly 10% after the company reported second-quarter revenue that exceeded market expectations and forecast strong growth in the third quarter, indicating that strong digital ad spending on its platform could offset the costs of its AI investments.