Check out the companies making headlines before the bell:

Shutterfly – Shutterfly agreed to be bought by private-equity firm Apollo Global for $51 per share, or about $1.7 billion. Apollo is also buying another online photo service, Snapfish, for about $300 million and plans to combine the two.

Barnes & Noble – A new bidder has emerged for bookstore chain Barnes & Noble, according to the Wall Street Journal. Book distributor Readerlink is said to be working toward a bid that would top Elliot Management's deal to acquire Barnes & Noble for $6.50 per share or $475 million in cash.

Beyond Meat – Short sellers have lost more than $400 million betting against the plant-based burger maker's stock since it went public, according to research firm S3 Partners. The stock is up about 600% from its $25 per share IPO price. Separately, J.P. Morgan Securities downgraded the stock to "neutral" from "overweight," saying its above-the-Street estimates now appear to be priced into the stock.

HD Supply Holdings – The industrial distributor reported adjusted quarterly profit of 84 cents per share, 3 cents a share above estimates, with revenue very slightly above Wall Street forecasts. Organic sales were up 5.8% from the year-ago quarter.

Ascena Retail – Ascena reported an adjusted quarterly loss of 26 cents per share, smaller than the 37 cents a share loss expected by Wall Street analysts. The parent of the Ann Taylor and Lane Bryant clothing brands saw revenue come in below estimates, however, and the company reported flat same-store sales.

Chico's FAS – The apparel seller reported adjusted quarterly profit of 5 cents per share, 2 cents a share above estimates. Revenue also beat Street forecasts, however, a comparable store sales decline of 7% was larger than the 6.6% drop that analysts had anticipated.

Casey's General Stores – Casey's reported quarterly profit of 68 cents per share, well above the consensus estimate of 46 cents a share. The convenience store operator's revenue also topped forecasts.

Broadcom – The chip maker announced a two-year supply deal with Apple, agreeing to provide components for smartphones, tablets, and smart watches.

Zynga – Zynga proposed a $600 million private debt offering, with that debt convertible into cash, stock, or a combination of the two. The mobile gaming company said the proceeds would be used for general corporate purposes.

Dollar Tree – Dollar Tree was upgraded to "overweight" from "neutral" at J.P. Morgan Securities, based on good metrics and improvements being implemented at the discount retailer's Family Dollar chain.

Wells Fargo – Wells Fargo was downgraded to "underweight" from "neutral" at Atlantic Equities, based on a decreased outlook for interest rates and increased competition for deposits.

Facebook – Moffett Nathanson upgraded the stock to "buy" from "neutral," reversing a call it had made last September. The firm said that multiple concerns it had expressed at that time have been addressed.