• from 3.8 million shares (worth $1.8 billion)
• to 4.7 million shares (worth $2.4 billion).

Why this was considered news, given that Icahn disclosed it three weeks ago, was not clear from their reports.

Their reports also failed to put those 4.7 million shares into any kind of context — starting with what percentage of Apple’s total shares they represent.

For the record, there were 899.74 million shares of Apple outstanding as of Sept. 30. That means Icahn’s holdings went from

• 0.4% in September to
• 0.5% in October

When Icahn tweeted last summer that he had taken a “large position” in Apple, he must have meant large in terms of dollars.

Because in terms of percentage of shares outstanding, his position in Apple is relatively small (assuming he hopes to use it as leverage to bend the company to his will). That usually requires something closer to a 10% stake (see attached chart).

Icahn is rich, but not that rich. He could put his entire $20 billion net worth into Apple, and still own less than 5%.

This may help explain why Tim Cook has so far declined to take Icahn’s advice and put all of Apple’s $150 billion cash holdings in a massive one-time stock buyback.

See: Carl Icahn ups his stake in Apple to $2.5 billion.