Buying LinkedIn means Microsoft will control the best-known network.
Tech companies typically do lots of business overseas and book profits in low-tax jurisdictions.
Fears of Chinese economic troubles and slowing iPhone demand vaporized more than $100 billion of the company's value since mid-July, reducing its market capitalization to $630 billion.
The $9.5 billion Nokia deal was the last in a string of bad deals struck by Chief Executive Satya Nadella's predecessor, Steve Ballmer.
Shareholders may once again be underestimating the staying power of the company's margins.
It's free cash flow over the past 12 months was more than $3 billion.