According to @KobeissiLetter, the largest 100 US companies now account for roughly 68% of total US market capitalization, the highest concentration since the 1970s (source: https://twitter.com/KobeissiLetter/status/1996274986760470859). According to @KobeissiLetter, this share has increased by 23 percentage points over the past 20 years (source: https://twitter.com/KobeissiLetter/status/1996274986760470859). According to @KobeissiLetter, the S&P 500 excluding the top 100 has fallen over the referenced period, underscoring a dominance of mega-cap leadership that is directly relevant for index-weighted exposure and breadth-sensitive strategies (source: https://twitter.com/KobeissiLetter/status/1996274986760470859).