This despite the fact the Herfindahl-Hirschman Index, a measure of industry concentration, has soared from 2200 to 2800.

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And while the DOJ makes much of the Herfindahl-Hirschman Index, a measure of industry concentration that would leap if the merger goes through, a court victory will depend mostly on whose experts are more convincing.

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Younger Internet users over-index on Tumblr, with the heaviest concentration falling between ages 18 and 24, according to ComScore.

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By way of example, the heavy issuance over the past several years of U.S. Government debt has increased the concentration of government-related securities in the Barclays Aggregate index, the customary benchmark for taxable fixed income mandates.

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