In the second quarter the bank reported a net loss of $2.4bn, driven by $8.4bn in provisions for future credit losses.
Wells chief executive Charles Scharf, who took the helm late last year, has committed to major cost cuts and has appointed new executives, many of whom worked with him at JPMorgan Chase. The appointees include a new chief financial officer, chief operating officer, leader of the credit cards division, head of public affairs and chief compliance officer.
Berkshire has also reduced its exposure to other banks this year, closing its position in Goldman Sachs and significantly reducing its stakes in JPMorgan and PNC Financial. At the same time, however, it has increased its exposure to Bank of America by $2bn since the end of the second quarter, leaving it with a $22bn investment.
As Berkshire has reduced its bank exposure, the conglomerate has added to its positions in Apple and, recently, purchased a small stake in Barrick Gold, despite Mr Buffett's historical scepticism about precious metals.
It has also invested $6bn in five of Japan's big trading houses, which are shifting from commodities to venture capital and private equity and whose conglomerate structure is not unlike Berkshire's own.