Mylan , Chesapeake Energy, Fortinet, Medtronic and Hain Celestial are big market movers

Stocks that moved substantially or traded heavily Friday on the New York Stock Exchange and the Nasdaq Stock Market:

NYSE

Medtronic Inc., up $2.22 to $65.02

The medical device maker switched to $16 billion in financing to buy Covidien after the U.S. restricted tax-saving, overseas deals.

Diamond Offshore Drilling Inc., down $1.83 to $33.00

The entire energy complex is under pressure, particularly oilfield service companies, as the price of crude continues to slump.

Penske Automotive Group Inc., up $2.46 to $43.55

Warren Buffett's acquisition of a big auto retailer pushed the entire sector higher as the billionaire talks market consolidation.

Chesapeake Energy Corp., down 48 cents to $21.75

The government reported a surge in natural gas supplies this week, pushing prices down and pressuring shares of drilling companies.

Nasdaq

Mylan Inc., up $3.73 to $50.23

The generic drug maker boosted its outlook for the third quarter and the year thanks to new drug launches and drug approvals.

Fortinet Inc., up 56 cents to $25.55

News of a massive data breach at JPMorgan Chase, the nation's biggest bank, sent shares of major tech security companies higher.

Jack in the Box Inc., up $1.49 to $68.86

The burger restaurant hit an all-time high after its Mexican chain Qdoba went after competitors with free extras like guacamole.

The Hain Celestial Group Inc., up 30 cents to $103.30

The health food company's buying spree is getting Wall Street's attention as Americans shift away from frozen or processed food.