This time four years ago, Warren Buffett was publicly campaigning for Hillary Clinton, even planning a trolley ride to the polls with Omaha voters. The billionaire’s schedule looks a little different ahead of the 2020 election, however. Notably, it lacks any public political engagements. Buffett has yet to raise funds or campaign for this year’s Democratic presidential nominee, former vice-president Joe Biden, The Wall Street Journal’s John McCormick and Catherine Lucey reported Sunday. A representative for Buffett at Berkshire Hathaway did not immediately respond to Business Insider’s request for comment on the CEO’s support of or involvement with the Biden campaign. The Biden campaign also did not respond to requests for comment. Warren Buffett’s ‘most gruesome mistake’ The issue isn’t that the billionaire is unsure of who to support, according to The Journal . Buffett criticised President Donald Trump’s refusal to release his tax returns in 2016, and is believed to have been referencing Trump when he wrote that “it is beyond arrogance for American businesses or individuals to boast that they have ‘done it alone’” in his 2019 shareholder letter. Buffett is a long-time Democrat. The CEO hosted a high-dollar fundraiser for President Barack Obama’s re-election campaign in 2011, and served as his unofficial economic adviser. Ahead of the 2016 election, Buffett spoke at a campaign rally for Clinton. The so-called “Oracle of Omaha” has kept a low profile overall since the coronavirus pandemic gripped the United States in June, appearing most recently during a live-stream of Berkshire Hathaway’s annual shareholder meeting in May. The Journal’s McCormick and Lucey floated the idea the Buffett’s well-documented dislike of the type of virtual gathering embraced by Biden could be a factor in his absence from the campaign, recounting the billionaire’s comment that a colleague easily surpassed his knowledge of Zoom in no time. Buffett’s prediction for America after Berkshire Hathaway’s US$50 billion loss Aside from the pandemic, the past few months have been rough on Buffett financially. Buffett’s personal fortune has declined US$7.3 billion in the past year, Business Insider previously reported – more in dollar terms than anyone else on the Forbes 400 list of richest Americans. Buffett remains ranked as the fourth-richest person in America, however. Even without Buffett’s support, Biden has received donations from dozens of billionaires, far more than President Trump. Read Business Insider’s story here .