Anglo formally offered the Botswana government a pro-rata share of the Oppenheimer family's 40% stake under a long-standing pre-emption agreement. However, Botswana declined to raise her stake in De Beers as this would have set back her efforts to diversify the economy away from its heavy reliance on diamonds.   http://www.miningweekly.com/article/botswana-declines-option-to-raise-de-beers-stake-2012-07-31