U.S. stock futures declined Wednesday morning following a market reversal that began after stocks initially rallied on news of the Supreme Court's decision against major portions of President Trump's tariff program. The high court's ruling limited presidential authority on tariffs, creating uncertainty about future trade policy direction.

Investors shifted from optimism to caution as they digested the implications of the court's decision. The tariff uncertainty prompted selling across global markets, with futures contracts indicating lower opening bell trading. Business leaders expressed concern about unpredictable trade policies affecting supply chains and pricing strategies.

The market volatility reflects broader anxiety about trade policy stability. Companies with significant international exposure saw particular pressure, while the U.S. dollar strengthened against major currencies as investors sought safe-haven assets. Market participants will continue monitoring for clarity on tariff implementation and potential policy responses.

Economists warn the tariff uncertainty could impact economic growth projections. The Supreme Court decision represents a significant check on executive authority in trade matters, potentially reshaping how future administrations approach international trade agreements and tariff implementation.