U.S. stock markets have shown significant gains recently, with the SPDR S&P 500 ETF Trust (SPY) up 3.5%, the Invesco QQQ Trust (QQQ) rising 3.6%, the SPDR S&P MidCap 400 ETF Trust (MDY) increasing by 4.1%, and the iShares Russell 2000 ETF (IWM) also up by 3.5% as of February 6, 2025. However, the technology sector, represented by the Technology Select Sector SPDR Fund (XLK), has lagged, rising only 0.7%. Notably, the concentration of the largest U.S. stocks has reached alarming levels, with the so-called 'Magnificent 7' now accounting for approximately 32% of the S&P 500, a significant increase of 10 percentage points over the past 1.5 years. This concentration is higher than during the 2000 Dot-Com Bubble. Additionally, U.S. leveraged ETF assets under management are nearing $110 billion, just shy of an all-time high, having tripled since 2022, indicating a surge in market speculation. The current market dynamics suggest a potential risk of dismal returns over the next five years due to this extreme concentration.