Key TakeawaysMacy’s shares could remain in focus on Tuesday after the struggling department store said holiday quarter sales may be slightly below expectations due to underperforming stores.Selling in the stock has intensified after it ran into resistance near the the upper trendline of a descending channel and the 200-day moving average.Investors should watch important support levels on Macy's chart around $13 and $10.75, while also observing key resistance levels near $18 and $20.50. Macy’s (M) shares cou ...