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Update of the post from mid -2025
In 2025, U.S. financial markets experienced repeated volatility driven by policy announcements from President Donald Trump. Approximately 150 announcements were issued throughout the year, spanning tariffs, trade measures, regulatory changes, and enforcement actions. The timing of these announcements by day of the week and relative to market hours was strongly correlated with market reactions, especially for the S&P 500, tracked by SPY, as well as the Dow Jones and Nasdaq.
Trade policy, particularly tariffs, was the most significant market moving category. Major tariff announcements produced intraday SPY moves exceeding 2 percent, with extreme cases in early April 2025 producing declines of 5 to 6 percent. Pauses or rollbacks of these tariffs often generated stronger rebounds than the initial selloffs.
Analysis of announcement timing reveals clear patterns:
Wednesday: The highest concentration of impactful announcements occurred on Wednesdays. Tariffs, trade letters, and regulatory updates were often scheduled midweek, resulting in strong intraweek volatility. SPY frequently reacted immediately, with some sectors, such as IT and defense, outperforming while consumer, retail, and EV equities lagged.
Thursday: Thursdays also contained a large number of announcements. Often, tariff expansions or clarifications from Wednesday carried over into Thursday, prolonging market reactions. SPY and Nasdaq regularly extended declines during these sessions, with the largest moves in trade-sensitive sectors.
Monday: Monday sessions reflected both overnight and weekend news. Weekend leaks of tariff updates or regulatory changes often produced sharp price gaps at the open. Markets digested these developments throughout the session, frequently showing SPY weakness in response to heightened uncertainty.
Tuesday: Tuesday reactions depended heavily on Monday’s announcements. When new information or confirmations were issued on Monday after market close or during pre-market hours, selling pressure carried into Tuesday. Market moves were often less volatile than midweek shocks but still significant for specific sectors.
Friday: Fridays were typically less impactful but occasionally reflected continuation of the week’s trend or reactions to late announcements. SPY and other indices often consolidated or closed lower if midweek news had unsettled markets.
After Market Close: Announcements released after market close created overnight volatility, influencing futures and the following day’s open. These events frequently led to large opening gaps, especially when tariffs, trade deadlines, or enforcement actions were involved.
Pre-Market Announcements: News issued before the opening bell directly influenced intraday price action. Tariff confirmations, new trade measures, and regulatory orders often caused immediate selloffs or rallies, with high volatility in the first few hours of trading.
Weekend Leaks: Announcements or leaks over the weekend had disproportionate effects on Monday trading. Markets frequently opened sharply lower or higher depending on the perceived significance of the news, producing large initial SPY moves before intra-day adjustments.
Across the 150 announcements in 2025, the observed patterns are as follows:
• 35–40 percent of high-impact announcements occurred on Wednesday
• 25–30 percent occurred on Thursday
• 10–15 percent occurred on Monday (mostly reflecting weekend leaks)
• 10–15 percent occurred on Tuesday
• 5–10 percent occurred on Friday
• Approximately 15 percent of announcements were released after market close, producing overnight futures volatility
• About 10 percent of announcements occurred pre-market, leading to immediate intraday market responses
• Weekend leaks and announcements accounted for roughly 10 percent of events, typically driving large Monday opens
Sector reactions were consistent with timing effects. Defense, IT, and domestic production-sensitive equities often outperformed on midweek announcements, while consumer, retail, EV, and renewable energy stocks were most vulnerable to downside shocks from tariffs, trade restrictions, or policy reversals. Symbolic political announcements, pardons, or culturally oriented communications generally had minimal index impact but occasionally produced volatility in niche stocks.
In conclusion, 2025 demonstrated that the day of the week and timing relative to market hours played a crucial role in market response to presidential announcements. Wednesday and Thursday were the most impactful, after-market and pre-market releases produced strong directional gaps, and weekend leaks disproportionately affected Monday trading. Despite repeated shocks, SPY and major indices ended the year up more than 16 percent, reflecting overall market resilience amid heightened policy-driven volatility.