Stocks in the news: Rio Tinto, Berkshire Hathaway, Microsoft

The following post rounds up the companies making headlines today:

Rio Tinto (RTP) was accused by China for spying on Chinese steel mills for six years, resulting in the mills overpaying $102 billion for iron ore, Rio Tinto's biggest earner. Rio Tinto declined to comment on the accusations, which may be something new according to Australia's ministry and the writer. Nonetheless, four Rio employees remain detained in Shanghai on suspicion of stealing state secrets. Shares declined about 4 percent ahead of the bell.

Berkshire Hathaway (BRK.B) posted a 14 percent rise in quarterly net income to $3.3 billion in net income, or $2,123 per share, after markets closed Friday. The improving stock market boosted the value of Warren Buffett's company's derivative contracts and its investments. Results were well above analyst estimates.