As the U.S. stock market approaches the critical moment of the "most important earnings report in the universe," investors are actively positioning themselves in preparation for potential volatility.After the market close on Wednesday, NVIDIA will announce its Q4 earnings report for fiscal year 2025, which could not only trigger fluctuations in tech stocks but also potentially influence the direction of the entire market. Although the S&P 500 index has recently hovered near historical highs and the fear index (VIX) remains well below its five-year average, deeper concerns are accumulating.According to Bloomberg, last week, the ratio of open interest in VIX call options to put options approached its highest level since September 2023, with trading volume in VIX call options exceeding 1 million contracts on Tuesday, indicating an increase in investors' expectations for rising volatility and hedging demand.As a leader in the artificial intelligence sector, NVIDIA's stock price has risen over 200% since its low in October 2023, with a market capitalization reaching $3.3 trillion, making it the second-largest component of the S&P 500 index, significantly increasing the market's sensitivity to NVIDIA's stock price fluctuations.As of last Friday, options traders expected a volatility of 7.7% for NVIDIA's stock price following this earnings report, lower than the average volatility of 9.2% over the past eight quarters. Around NVIDIA's earnings report date, the average volatility of the S&P 500 index was 0.8%, higher than the average daily volatility of 0.6% for the index over the past two years.Amy Wu Silverman, head of derivatives strategy at RBC Capital Markets, stated:"NVIDIA's earnings report and the resulting volatility will undoubtedly impact broader market volatility. Any performance that exceeds or falls short of expectations will have a ripple effect on AI and related sectors."It is noteworthy that the hedge fund market's performance is relatively average, which may indicate that risks have accumulated.As of February 18, the net short position of hedge funds in VIX futures was close to its highest level in seven months. According to the latest data from the Commodity Futures Trading Commission (CFTC), the last time such a low net short position was observed was before the volatility shock in early August last year.In addition to NVIDIA's earnings report, several other significant events that could trigger market volatility are expected in the coming weeks: the Trump administration's exemption from steel and aluminum tariffs for Canada and Mexico will expire on March 4; the U.S. non-farm payroll report will be released on March 7; and the government budget negotiation deadline is March 14.Brent Kochuba, founder of SpotGamma, also commented:"NVIDIA indeed has the potential to influence the direction of the entire stock market. In the coming weeks, several factors, including tariff policies and government shutdown deadlines, could trigger a surge in volatility."Chris Murphy, co-head of derivatives strategy at Susquehanna International Group, warned:"If negative tariff news emerges, causing stocks to begin moving in sync or highly correlated, we could see volatility spike sharply."