Motsepe made his announcement on Wednesday in Johannesburg, amid speculation he was going to buy South Africa's Independent Newspaper Group from major shareholders Independent News and Media. Rumours also circled African Rainbow Minerals, of which he is the founder and executive chairperson, would make purchases in the platinum sector.
According to Forbes, Motsepe's net worth alone is at $2.65-billion as of November 2012.
Motsepe said the money given to the Motsepe Foundation would contribute in particular to addressing education and health issues in South Africa.
In a live video at the event, billionaire and philanthropist Bill Gates commended Motsepe's decision.
The announcement was attended by the likes of King Goodwill Zwelithini, Basic Education Minister Angie Motshekga, Rabbi Warren Goldstein and other religious leaders.
Motsepe was recently in Davos – as was Denis O'Brien, Independent News and Media's biggest shareholder who met with President Jacob Zuma around "shareholdings in South Africa" – and expressed an interest in the media group, according to Bloomberg, leading to speculation he wanted to buy the South African media arm of the Irish publishing company.
Motsepe also expressed an interest in extending his holding in platinum, leading to discussions that his announcement might be related to the four shafts in Rustenburg that Anglo American Platinum is looking to mothball.
While in Davos he told Bloomberg that African Rainbow Minerals regarded platinum as a key sector and that they were looking for opportunities to buy platinum mines.
African Rainbow Minerals and Anglo American Platinum already have a joint venture at Modikwa Deep.