Berkshire Hathaway's $1 billion homebuilding investment indicates Warren Buffett's confidence in a future U.S. housing market rebound.

Nucor is one of the largest and most diversified North American steelmakers. It uses electric arc mini-mills, which are more flexible than older blast furnaces. Nucor can, basically, ramp up and down with steel demand, allowing it to have stronger margins through the entire steel cycle. The steel cycle is important here.

Warren Buffett’s Berkshire Hathaway revealed a position in embattled healthcare giant UnitedHealth Group while showing smaller stakes in longtime holdings Apple and Bank of America, according to a regulatory filing Thursday.