Berkshire Hathaway Inc., the company that agreed to buy Burlington Northern Santa Fe Corp. in its biggest takeover, accepted a lower-than-usual breakup fee in a sign Warren Buffett expects no one will top his bid.

Berkshire will receive $264 million if Burlington, the biggest U.S. railroad, cancels the agreement, according to a filing yesterday. That’s less than 1 percent of the deal’s value including net debt and compares with the 2 percent to 3 percent that is typical of these deals, said Elizabeth Nowicki, a professor at Tulane University Law School.

“Berkshire recognizes there’s a very, very small chance Burlington is going to have the desire or the opportunity to back out,” Nowicki, who is a former mergers and acquisitions lawyer at New York-based Sullivan & Cromwell LLP, said in an interview. “In this difficult economy, I doubt the Burlington board is going to have other bidders wanting to acquire them.”

Buffett, who built Berkshire over more than four decades, is taking on debt and spending the company’s cash as the economic crisis curbs expansion at some U.S. firms. Berkshire agreed to pay $26 billion for the 77.4 percent of Fort Worth, Texas-based Burlington it didn’t already own and assume $10 billion in net debt.