The excellent analyst website asymco.com recently published a post titled Visualizing the Steve Jobs era. In it they display an area chart of the relative size of market capitalization of about 15 companies they have tracked for the last 15 years.

Since I had looked at the Gini index of a similar set of companies in an earlier post on Visualizing Inequality I contacted the author Dirk Schmidt. Thankfully he shared the underlying data. From that I calculated the Gini index for every quarter and overlaid a line chart with their area chart.

Share of Market Capitalization Area Chart overlaid with Gini Index

Dirk elaborated in his post and identified three distinct periods in his post:

• Restructuring of Apple 1997-2000 – Gini remains very high near 0.85 due to MSFT dominance
• iTunes era 2001-2006 – Gini decreases to ~ 0.55 due to AAPL increase and taking share from other established players
• Mobile devices era 2007-2011 – Gini increases again to 0.65 due to increasing dominance of AAPL and irrelevance of smaller players

Regardless of the absolute value of the Gini index – note the caveat from the earlier post that it is very sensitive to the number of contributors – the trend in the Gini can be an interesting signal. One company dwarfing every other like a monopoly corresponds to high Gini (here 0.85 due to MSFT dominance). A return to lower Gini values (here down to ~0.5) signals stronger competition with multiple entrants. The recent reversal of the Gini trend (up to 0.65 due to AAPL dominance) is a sign that investors see less choices when it comes to buying shares in those tech companies. Whether that’s a leading indicator for consumers seeing less choices in the marketplace is another question…