Cigna, Martha Stewart, Williams, American Airlines and Epizyme are big market movers

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

NYSE

Cigna Corp., up $7.34 to $162.60

The health insurer rejected a $47 billion buyout offer from rival Anthem Inc., saying the terms of the deal were inadequate.

Williams Cos., up $12.52 to $60.86

The gas pipeline company rejected a $48 billion takeover offer from Energy Transfer Equity but said it may still be for sale.

Martha Stewart Living Omnimedia Inc., down 86 cents to $6.12

Sequential Brands Group Inc. is buying the media and merchandising company for about $353 million in a cash-and-stock deal.

National Bank of Greece SA, up 20 cents to $1.30

The bank's stock gained ground on hopes that there will be a breakthrough in Greece's bailout negotiations with creditors.

Nasdaq

American Airlines Group Inc., up $1.47 to $43.03

The airline and its rivals saw shares rise after two analysts suggested that investors are too gloomy about the shares.

Epizyme Inc., up $5.23 to $25.98

The biotechnology company reported positive data from an early stage clinical trial of a cancer treatment.

American Micro Devices Inc., up 4 cents to $2.62

The chipmaker hired a consulting firm to review whether the company should split its business, according to a Reuters report.

Noodles & Co., down 58 cents to $16

The casual restaurant operator's president and chief operating officer is leaving to become CEO of an unnamed restaurant business.