Charities including the Bill & Melinda Gates Foundation are said to be bracing themselves for potential changes in Warren Buffett's philanthropy plans. Speculation is said to be building around how the billionaire mogul plans to divide his estate, with truly staggering sums of money set to be up for grabs. Preparations are currently underway at a Buffett family foundation which supports abortion rights to receive as much as $100 billion when the nonagenarian tycoon passes away, according to the Wall Street Journal. Similar plans have reportedly been made at Gates’ charity for years. Buffett, 91, has previously committed to giving away 99 percent of his fortune, which is currently estimated to be worth around $90 billion. Despite making an annual gift of Berkshire Hathaway shares to charitable causes every year—the majority of which goes to the Gates Foundation—exactly how his estate will be divided remains to be seen.