(Updates with index/price moves and company news from the first paragraph.)

US equity indexes fell after semiconductor companies slumped while mega-cap banks posted mixed quarterly results.

The Nasdaq Composite fell 0.1% to 27,226.5, the S&P 500 slipped less than 0.1% to 7,803.1, and the Dow Jones Industrial Average declined 0.3% to 51,682.3.

Among stocks with market capitalization exceeding $200 billion, as many as seven of the bottom 10 were technology names, according to data compiled by Finviz.

Micron Technology (MU) led the decliners in this mega-cap category, down 5.2%, after media outlets reported that China's CXMT claimed a breakthrough in DRAM technology and a new 4F2 data center chip design slated for launch by year-end.

The iShares PHLX Semiconductor ETF (SOXX) fell 2.1% after midday, its sixth consecutive day of declines.

Wells Fargo (WFC) shares slid 1.8% after the lender missed Q3 revenue consensus estimates.

Citigroup's (C) Q3 results beat consensus, underpinned by double-digit revenue growth in services and wealth segments, while the banking giant raised its net interest income outlook. Nevertheless, its shares dropped 3.5%.

Goldman Sachs (GS) rose 0.7% after reporting Q3 earnings and net revenue above consensus estimates.

JPMorgan Chase (JPM) reported Q3 earnings that were up from a year earlier but below market expectations. Its shares traded 0.3% higher.