Warren Buffett’s highly anticipated – and usually entertaining – annual letter to Berkshire Hathaway shareholders will not arrive for at least a few more weeks. But many investors can probably guess at least one key theme to the latest dispatch: it was a tough year for both Mr Buffett and Berkshire.

Berkshire’s profit has slumped for five consecutive quarters, a streak expected to continue when the company reports its fourth-quarter results. Its class A shares have dropped 37 per cent since the start of 2008, battered by concerns for Berkshire’s derivatives losses and portfolio of financial stocks, barely besting the benchmark Standard & Poor’s 500 Index during that period.