目前支撐這種極端估值的主要動力來自於人工智慧（AI）相關產業的繁榮，市場對科技巨頭和晶片供應商未來的龐大獲利抱持高度期待。然而，歷史上的重大技術創新往往伴隨著過度投資、激烈競爭和企業破產潮，無法保證絕對的豐厚利潤。除非未來能實現生產力的大幅提升或資本收益的結構性轉變，否則當前的AI狂熱可能難以長期支撐如此不合理的市場定價。
儘管市場沉浸在樂觀情緒中，但許多潛在的系統性風險正對全球經濟構成威脅，隨時可能成為引發股市崩盤的導火線。這些風險因素包含美國政府的高額財政赤字、全球公私部門創紀錄的債務水平、地緣政治的動盪與貿易戰、去全球化趨勢，以及非銀行金融機構帶來的金融脆弱性。面對這些不可忽視的威脅，投資者應審慎評估風險，並考慮採取避險措施以保護自身資產。
In 2026, the valuation of the US stock market has reached historic highs, surpassing even the levels seen just before the Great Crash of 1929 and second only to the peak of the 1999 dotcom bubble. Economists utilizing metrics such as the cyclically adjusted price-to-earnings (CAPE) ratio and the "Buffett indicator" point out that current market pricing is extremely expensive. Historical trends strongly suggest that when stock valuations reach such extreme levels, they are often followed by severe market crashes and extended periods of poor returns.
The primary driver sustaining these extraordinary valuations is the boom surrounding artificial intelligence (AI), with the market holding high expectations for massive future profits from tech giants and chip suppliers. However, history demonstrates that major technological innovations are frequently accompanied by over-investment, fierce competition, and waves of bankruptcies, rather than guaranteed massive profits. Unless there is a significant surge in productivity or a structural shift in capital gains, the current AI frenzy may struggle to justify such irrational market pricing over the long term.
Despite the prevailing market optimism, numerous underlying systemic risks are threatening the global economy and could act as catalysts for a severe stock market correction at any moment. These risk factors include massive US government fiscal deficits, record-high public and private debt levels globally, geopolitical turmoil and trade wars, deglobalization trends, and the financial fragility introduced by non-bank financial institutions. In the face of these substantial threats, investors are advised to carefully evaluate their risks and consider hedging strategies to protect their assets.