"It doesn't influence my decision at all; never has, never will," Nelson says. He says he owned the stock before his time as Nebraska's Governor in 1991 to 1999, and his wife has held her stock for three decades.
According to his 2008 disclosure form, Nelson and his wife own between $1.5 and $6 million worth of shares in Warren Buffett's company. The Center for Responsive Politics says that's the most Berkshire stock held by any member of Congress.
Nelson was the only Democrat to vote with Republicans who have successfully blocked consideration in the Senate of a finreg bill over the past two days.
The Wall Street Journal and others have reported that Nelson pushed for an exemption from derivatives rules sought by Berkshire Hathaway. That exemption is not in the current version of the Democrats' proposed finreg bill.
Bloomberg says when Nelson was asked if the absence of an exemption for collateral requirements on already-existing derivatives contracts would ultimately prompt him to vote no, he replied, "I am looking to be in favor of the bill, I just want to make sure it does in fact deal with the Wall Street issues and not overextend to deal with Main Street issues that are not part of the problem... (I'm) hopeful that these matters will be taken care of (because) you can't take property." He's concerned that if the legislation isn't "done right," it won't stand up to a constitutional challenge.
Nelson also told reporters he and his staff haven't talked to Buffett himself on the issue, but have consulted with Berkshire representatives "all along the way," to "understand the issue and why it's important."
The New York Times Caucus blog says some Democrats, including bill-sponsor Senator Christopher Dodd of Connecticut, have speculated Nelson is opposing the current version due to his relationship with Buffett, a fellow Nebraskan.
The Center for Responsive Politics lists Berkshire, and individuals connected to the company, as Nelson's second biggest campaign contributor between 2005 and 2010.
Current Berkshire stock prices: