Today’s midday gainers are Boyd Gaming Corporation (NYSE:BOYD), J.C. Penney Company, Inc. (NYSE:JCP) and Zulily Inc (NASDAQ:ZU). Down are Myriad Genetics, Inc. (NASDAQ:MYGN), Post Holdings Inc (NYSE:POST) and Ruckus Wireless Inc (NYSE:RKUS).

chart_1 (22) Boyd Gaming

Boyd Gaming Surges on Elliott Associates News

Up +18.39%, Boyd Gaming Corporation (NYSE:BYD) is this Tuesday’s top midday gainer. The jump comes after Elliott Associates confirmed that it has a 5% stake in the company. David Tepper has a 787,000-share stake in Boyd Gaming.

Also having a solid day is J.C. Penney Company, Inc. (NYSE:JCP), the price of which surged +9.06% midday today and is up +24.86% this month. Citigroup has raised its recommendation for JCP shares to buy from neutral. George Soros has a position in the retail giant.

Zulily Inc (NASDAQ:ZU)’s share price increased +7.59%, taking the third spot on today’s list of midday gainers. The Tiger Global pick continues its impressive post-earnings rally and is up +49.85% since reporting results on February 24th.

Myriad Loses Ambry Genetics Battle, Takes a Dive

Myriad Genetics, Inc. (NASDAQ:MYGN) dipped -9.48% today. Also a Tiger Global pick, the molecular diagnostics company has lost a hard-fought battle to block Ambry Genetics from selling a similar version of its cancer test.

Down -7.94% is Post Holdings Inc (NYSE:POST), which updated and lowered its guidance based on operations costs adjustments. Both Tiger Global and John Paulson have positions in the cereal company.

Last on our losers list for midday today is Ruckus Wireless Inc (NYSE:RKUS). Shares of the Wi-Fi solutions provider are down -6.48%. The company struck a deal with Deep Blue Communications and had its rating upgraded yesterday, but investors apparently remain wary.