Warren Buffett tells Omaha gathering he may buy more newspapers Given the $200bn market value of Berkshire, Mr Buffett has admitted that he needs to make larger acquisitions to generate the sort of returns that have marked the company for much of its history. Berkshire could make a $30bn acquisition next year, he said. This year's shareholder gathering comes six months before a presidential election in which a proposal by Mr Buffett calling for America's richest to pay higher taxes is expected to be one of the dividing lines between President Barack Obama and Mitt Romney, the likely Republican challenger. The billionaire today defended the Buffett Rule, arguing that it is aimed at lifting the tax rate of the country's very richest. "When you're asking for shared sacrifice from the American people, I would at least think that the people with these huge incomes get taxed at a rate commensurate with where they once were taxed," he said. During a day of questions, Mr Buffett also said Europe's financial system still faces challenges. "I have a decidedly different view on European banks than American banks," he said. American banks are in a far, far better position than they were a few years ago. They've got liquidity coming out of their ears. The billionaire also admitted that his successor will not be able to pull off some of the investments he has made in recent years. "I don't think every deal that I've made will be makeable by my successor," he said. The 81-year-old billionaire was referring specifically to investments he made in Goldman Sachs and insurer Swiss Re at the height of the financial crisis which reaped hundreds of millions of dollars in profit for Berkshire. Goldman turned to Mr Buffett for $5bn in September 2008, a move that helped restore investors" confidence in the Wall Street bank. Thousands of Berkshire shareholders made their annual pilgrimage this weekend to the Midwestern city of Omaha as the question of who will succeed Mr Buffett comes under ever closer scrutiny. Mr Buffett revealed last month that he has prostate cancer and begins two months of radiation therapy in July. In February, he said he has picked a successor, but did not give a name. The cancer is not life-threatening and Mr Buffett has no plans to retire. He added that the high-profile transactions, such as that with Goldman, which his reputation as an investor helped to seal, are not central to Berkshire's success. Instead, he said, the ability to make large investments quickly is more important and that will be available to whomever takes over.