On the evening of May 13th, US stock index futures traded steadily as investors closely watched the impending release of key inflation data, expected to impact interest rate trends, while so-called "meme stocks" continued to rise in after-hours trading.

Trading in US futures markets mirrored activity on Wall Street, with investors awaiting fresh interest rate clues ahead of inflation data releases on Tuesday and Wednesday. However, "meme stocks" were an exception, swiftly rising after Keith Gill, known as Roaring Kitty on social media, posted for the first time in three years. Nonetheless, their gains had minimal impact on the overall market.

As of 19:13 Eastern Time (23:13 Greenwich Mean Time), S&P 500 index futures edged lower to 5,243.50 points, Nasdaq 100 index futures declined 0.1% to 18,282.25 points, while Dow Jones index futures held steady at 39,556.0 points.

Wall Street experienced slight fluctuations with the release of Producer Price Index (PPI) and Consumer Price Index (CPI) data. Stock indices on Wall Street maintained narrow oscillations on Monday, with attention focused on producer and consumer price index data.

The PPI report is scheduled for release on Tuesday, while the more closely watched CPI data will be released on Wednesday. As these data emerge, first-quarter inflation has remained largely unchanged, deepening market doubts about the Federal Reserve's plans for interest rate cuts this year. Signs that inflation may continue to rise in April could dampen expectations of rate cuts in the market, potentially leading to a stock market decline.

In recent weeks, many Federal Reserve officials have also indicated a reluctance to begin rate cuts and hope to ensure more strongly that inflation returns to its annual 2% target.

On Monday, the S&P 500 index closed at 5,221.42 points, the Nasdaq index rose 0.3% to 16,388.24 points, while the Dow Jones Industrial Average fell 0.2% to 39,431.51 points.

Stocks of AMC Entertainment Holdings Inc. (NYSE: AMC) and GameStop Corp (NYSE: GME), known as "meme stocks," surged during trading and continued their upward trend in after-hours trading.

As a video game retailer, GME stock rose 74% in a day and another approximately 24% after hours, while AMC stock, as a cinema chain operator, rose nearly 80%. The buying frenzy spread to some other fundamentally weaker companies, which attracted retail traders in 2021 to boost stock prices.

In the US, shares of BlackBerry Limited (NYSE: BB) rose 12%, headphone manufacturer Koss Corporation (NASDAQ: KOSS) rose 9.2%, and Reddit Inc. (NYSE: RDDT), the platform that ignited much of the "meme stock" craze, rose nearly 2%.