The Lombard Review
Markets & Finance

A bull market built on seven stocks

Concentration risk in cap-weighted index

New York Stock Exchange signage on Broad Street
New York Stock Exchange signage on Broad StreetPhoto: Billie Grace Ward / Wikimedia Commons, CC0

The bull market has officially arrived, at least according to the arbitrary twenty per cent benchmark that equity commentators revere. Having rebounded from its October lows, the S&P 500 wears the mantle of a new economic dawn. Yet look beneath the glittering surface of the cap-weighted benchmark, and the breadth is startlingly anaemic. The entirety of the 2023 equity advance has been engineered by a tiny cadre of mega-cap technology monopolies, leaving the median constituent languishing in cyclical stagnation.

Market data screens at the Frankfurt Stock Exchange
Market data screens at the Frankfurt Stock ExchangePhoto: Ank Kumar / Wikimedia Commons, CC BY-SA 4.0

Monopoly Multiples

This extreme concentration creates profound structural fragility. Passive index flows automatically concentrate capital into the largest capitalization weights, driving valuations for the 'Magnificent Seven' to multiples that discount perfection decades into the future. A market rally predicated on seven corporate balance sheets is not a reflection of broad industrial vigour; it is a defensive capital stampede seeking refuge in cash-rich balance sheets.

The BlueScope steelworks at Port Kembla, Australia
The BlueScope steelworks at Port Kembla, AustraliaPhoto: Marek Ślusarczyk (Tupungato) Photo gallery / Wikimedia Commons, CC BY 3.0

When an entire benchmark relies on seven balance sheets to sustain its momentum, the line between a diversified investment vehicle and a levered momentum hedge fund becomes dangerously blurred.