Former Orica chief Malcolm Broomhead is Australia’s most connected corporate director.

In exclusive data compiled for The Power Index by ASX data specialists Optimice to round off our extensive 13-part investigation into boardroom power, Broomhead, who serves on the board of global miner BHP Billiton and chairs the country’s second-largest listed rail firm Asciano, boasts over $1.72 trillion in capital within one degree of separation.

That is, the total value of firms overseen by Broomhead’s colleagues on both boards is greater than each of the ASX’s other 7734 directors. By listing how “valuable” boardroom connections are for each board member, total influence — through formal negotiations and off-the-record conversations — can be measured.

The top 10 is dominated by BHP Billiton directors, based on market capitalisation of its Australian shares of $106 billion, according to the data compiled by Optimice and sourced from Thomson Reuters on October 26. The Power Index has allocated a “Broomhead index” of between 1 and 100 to other directors, to gauge their connectedness as a proportion of Broomhead’s heft …

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Sir John Buchanan — BHP’s senior independent non-executive director and remuneration committee chair — comes in at No. 2 with $1.48 trillion and a Broomhead index of 86, followed by BHP colleague and Lend Lease and Australia Pacific Airports Corporation chair David Crawford at No. 3 with $1.44 trillion and an index of 84.

By contrast, the least connected individual on the ASX is (recently resigned) Omnitech Holdings director Arthur Sturgess with just $50 at arm’s length and a Broomhead index of 0.

Miners continue to be dominant: if BHP’s total global market cap was included alongside that of main competitor Rio Tinto, the dual resources giants would be even more influential. Another jewel is News Corporation — most of that company’s directors appear in the top 50, including Australian Peter Barnes at No. 34 with $554 billion and an index of 32.

Women are significantly under-represented, comprising just 14 of the top 50 and two of the top 10. Exclude BHP and their presence would be even further marginalised.

The Market Capitalisation Influence Index connectedness ranking was a major factor in deciding The Power Index No. 1 ranking snagged by the country’s premier corporate whisperer David Gonski. The individual MCII ranking — a raw measure of the value of companies controlled by individual directors — was taken out by Westpac and Transurban chair (and BHP director) Lindsay Maxsted.