Warren Buffett’s Berkshire Hathaway became the first publicly traded US company outside the technology sector to be valued at $1tn, as a small advance on Wednesday pushed its market capitalisation into a club that had been dominated by companies such as Apple and Microsoft.

The sprawling conglomerate has been transformed by Buffett over the past six decades into a force touching almost every corner of the American economy. Its rail cars traverse more than 32,000 miles of track that criss-cross the country, it owns a critical parts manufacturer for Boeing, and it runs one of the largest US auto insurers.

Buffett, who turns 94 on Friday, has spent the year selling off stocks — including half of the stake in Apple that generated a mammoth trading profit for Berkshire — and pumping the proceeds into cash and short-term Treasuries.