Shares of General Motors (GM  ) caught the attention of investors Thursday as the stock had a rare, 5.5% move. What is normally a "slow and steady" stock, today performed more like a tech stock as news came out about sales for the auto maker. The news sent shares up to new 2016 highs. This wasn't a shock to traders though. For the last few weeks large, institutional buying had been detected and many analysts were starting to respond with upgrades, and price target adjustments. Since the lows on November 9th GM is up almost 18%, basically moving in one straight line.

General motors said that sales were up 10.2% last month as fleet sales and the retail buyer showed strong demand. This performance beats the other five large automakers' performance which is part of the reason for the 5.5% spike Thursday. While the sales are impressive, many wonder if this is due to the rising incentives that the company offers.

According to TrueCar.com, it was estimated that GM had spent an average of $4,305 per vehicle sold on incentives in November alone. This is well above the industry average, but it seems to be working. GM said that these incentives drove its fleet sales up 19% which accounted for 22% of its overall sales.

So the question is "are the new buyers today justified in chasing the stock at these prices?"

Well, the market for new cars is cyclical and many analysts believe that the new car market is getting beyond its cyclical peak. GM, however can continue to point to strong sales as a metric that is contradicting the trend. Year over year sales have outpaced the five largest competitors, and although they did need to offer those incentives to attract new buyers, it seems that it worked.

Currently, most analysts are neutral to bullish on the stock with price targets from $37 up to $44. If $44 is correct that would mean there is still another 20% upside potential in GM.