NEW YORK (AP) — Stocks that moved substantially or traded heavily Monday on the New York Stock Exchange and Nasdaq Stock Market:

NYSE

Chesapeake Energy Corp., up 94 cents at $16.52

The natural gas producer is replacing four of its board members, a week after activist investor Carl Icahn took a stake in it.

Delta Air Lines Inc., down $1.33 at $10.18

The airline said that a key measure of revenue rose less than it expected in May as it ran into fare discounting by a competitor.

Nasdaq

Smart Balance Inc., up $1 at $7.07

A Canaccord analyst upgraded shares of the food company saying its recent acquisition of a gluten-free food maker will boost growth.

Nathan's Famous Inc., up $1.50 at $26.50

The hot dog seller said that its fourth-quarter profits doubled and its branded product sales jumped more than 26 percent.

Conn's Inc., down 99 cents at $16.72

The retailer said its first-quarter net income more than doubled as prices increased. It also raised its outlook for the year. Shares fell as the broader market stalled.

Credo Petroleum Corp., up $3.49 at $14.35

Real estate and natural resources developer Forestar Group Inc. agreed to buy the oil and gas company for about $146 million.

Medtox Scientific Inc., up $6.98 at $26.68

The medical test service company reached a deal to sell itself to rival Laboratory Corp. of America Holdings for about $241 million.

The Cheesecake Factory Inc., down $1.06 at $30.29

A William Blair analyst downgraded shares of the restaurant operator saying consumers are again pulling away from dining out.