U.S. stock futures are headed higher amid light volume in this Thanksgiving-holiday-shortened trading week. Wall Street is gearing up for the holiday shopping season, and retailers are higher as Black Friday, the biggest shopping day of the year, approaches.

Meanwhile, traders are digesting news that Federal Reserve Chairwoman Janet Yellen will leave the central bank completely, rather than stay on as a Fed governor.

Heading into the open, Dow Jones Industrial Average futures are up 0.42%, while S&P 500 futures have gained 0.33% and Nasdaq-100 futures have rallied 0.45%.

On the options front, volume was light on Monday, with many traders heading for home early for Thanksgiving. Overall, about 15.3 million calls and 11.2 million puts changed hands. On the CBOE, the single-session equity put/call volume ratio rose to 0.59 and the 10-day moving average held at 0.65.

Diving into Monday’s options activity, Alibaba Group Holding Ltd (NYSE:BABA) delved further into brick-and-mortar retailing with a stake in China-based Sun Art Retail Group. Elsewhere, Micron Technology, Inc. (NASDAQ:MU) set the official date for its first-quarter earnings report, while AT&T Inc. (NYSE:T) is gearing up for a legal battle with the Department of Justice over its Time Warner Inc (NYSE:TWX) acquisition.

Alibaba Group Holding Ltd (BABA)

Alibaba, the world’s largest online retailing company, once again took aim at brick-and-mortar stores yesterday by taking a $2.9 billion stake in Chinese grocery firm Sun Art Retail Group. With roughly 400 hypermarkets across the country, Sun Art is Wal-Mart Stores Inc.’s (NYSE:WMT) biggest competitor in China. Alibaba now holds a 36% stake in Sun Art.

BABA options traders cheered the move, sending more than 256,000 contracts across the tape on Monday — roughly 1.3% of the stock’s daily average options volume. Calls made up an above average 63% of the day’s take.

The attention to bullish calls continues a shift in sentiment toward BABA stock, which has seen its December put/call open interest ratio decline in recent weeks. This sentiment indicator now rests at 0.92, which is still indicative of negativity toward BABA, but the shift toward calls should be a bullish driver for the shares.

Micron Technology, Inc. (MU)

Micron officially set the date for its fiscal first-quarter earnings report yesterday. The company will step into the earnings confessional on Dec. 19, with a conference call scheduled for 2:30 p.m. that day.

Wall Street is currently expecting a profit of $2.13 per share from Micron, up considerably from last year’s profit of just 32 cents per share. Revenue is expected to have surged 61% to $6.4 billion.

Options traders are already gearing up for the report. Volume on Monday rose to 237,000 contracts, with calls gobbling up 71% of the day’s take. Furthermore, the weekly Dec 22 put/call OI ratio has fallen to a reading of 0.43, with calls more than doubling puts among options most affected by Micron’s quarterly report.

Implieds are pricing in a potential post earnings move of about 10%, placing the upper bound near $52.50 and the lower bound near $42.80.

AT&T Inc. (T)

The Department of Justice has officially moved to block AT&T’s acquisition of Time Warner. The DOJ said the acquisition would reduce competition and lead to higher consumer prices. AT&T has vowed to fight the DOJ’s suit, calling it a radical departure from U.S. practice.

Options traders were mixed on the news, as it was a move many saw coming. Volume rose to 136,000 contracts, with calls eking out 53% of the day’s take.

Looking at December options, traders are largely positive on T stock’s prospects, with the put/call OI ratio arriving at a bullishly inclined 0.60. Peak call OI for the series totals 58,000 contracts at the $35 strike, while peak put OI numbers 38,000 contracts, also at the $35 strike.

As of this writing, Joseph Hargett did not hold a position in any of the aforementioned securities.