Among the companies with shares expected to actively trade in Monday's session are ATP Oil & Gas Corp. (NASDAQ:ATPG) and ZAGG Inc. (NASDAQ:ZAGG) .

ATP Oil & Gas for Chapter 11 bankruptcy protection Friday, hit by the rising costs associated with its deep-water drilling projects in the Gulf of Mexico. Shares slumped 59% to 19 cents after hours.

Mobile-device accessory maker ZAGG Inc. (NASDAQ:ZAGG) said its co-founder, Robert G. Pedersen II, resigned as chief executive and chairman. Shares fell 5.1% to $7.99 after hours.

Women's clothing retailer bebe Stores Inc. (NASDAQ:BEBE) said its president, Emilia Fabricant, resigned for personal reasons, effective Friday.

Carmike Cinemas Inc. (NASDAQ:CKEC) said it received a "nonspecific telephoned bomb threat" at its corporate offices in Columbus, Ga., after business hours on Thursday.

Energy Transfer Partners L.P. (NYSE:ETP) filed plans to offer up to $1 billion in common units and debt securities, as the pipeline operator looks to raise funds for general partnership purposes.