the 77.4 percent of Burlington Northern Santa Fe it did not already own for $34 billion in cash and stock, in the largest deal in Berkshire history.
But wait, they also assumed 10 billion in debt. So they just "spent" 34 billion buying sock + 10 billion debts to get the company.
PS: I don't know when BH got their initial stake, but they could have paid something like (34 / .774) = ~43.9 billion to get the company. Assuming the company was profitable and paying down the debt you can somewhat ignore it.
