The Canadian home lender fell 13.09% to $10.60 a share in midday trading Wednesday.
Berkshire Hathaway will "substantially exit" its stake in the company - it currently holds 24.64% of the outstanding shares, according to FactSet. So a big exit from that position, which Berskshire established only a year ago, both signifies falling confidence in the company and adds a lot of supply of shares onto the market.
When Berkshire took the stake last year it also provided the struggling lender with a line of credit, worth $1.5 billion.
Home Capital also announced Wednesday it would buyback roughly $223.5 million worth of its own stock. Berkshire will hold less than 10% of the company upon completion of the buyback.
Home Capital has fallen 16.12% this year, and was actually at a gain for the year in early December before the last few days.
The price of Berkshire Hathaway's A shares rose 1.71% to $299,540.