With earnings season (unofficially) under way, the Dow Jones Industrial Average (DJI - 13,317.55) is down 67 points, or 0.5%, as analysts' predictions for lackluster corporate growth for the fourth quarter have some investors on edge. Even so, the National Federation of Independent Business (NFIB) said its small-business optimism index arrived at 88.0 in December, up from the previous month's reading of 87.5. Elsewhere, the CBOE Market Volatility Index (VIX - 14.11) is 0.3 point, or 2.3%, higher after five days in negative territory.

Here are a few noteworthy stats at midday:

1. The equity put/call volume ratio across all 11 options exchanges checks in at 0.98, with 2.88 million calls changing hands so far today, versus 2.85 million puts.
   
   
2. Among the equities with call-skewed activity is Celgene Corporation (NASDAQ:CELG - 89.62), which has gained about 4.5%, and touched a new all-time high of $89.66. The stock was upgraded to "overweight" from "neutral" at Piper Jaffray this morning, after CELG revealed successful late-stage study results of its psoriasis drug, Apremilast. Currently, calls account for 60.1% of the biotech firm's intraday option volume. Meanwhile, Tesoro Corporation (NYSE:TSO - 40.96) is seeing 96.2% of its option volume trading on the put side of the aisle, despite an intraday rise of nearly 2%. The shares lost nearly 5.5% yesterday after a downgrade from Howard Weil.
   
   
3. The put/call volume ratio on the iPath S&P 500 VIX Short-Term Futures ETN (NYSEARCA:VXX - 27.49) -- which tagged a record low of 27.19 earlier in the session -- sits at 1.69, with puts comfortably outnumbering calls.
   
   
4. The New York Stock Exchange (NYSE) shows an advance/decline ratio of 0.66, with the number of downward movers easily outstripping the advancers.
   
   
5. Among the NYSE's major decliners is GameStop Corp. (NYSE:GME - 23.61), which has shed around 4.6% in intraday trading. The video-game retailer reduced the high end of its fourth-quarter outlook after holiday same-store sales fell by 4.4%. GME also warned of a 4%-to-7% decline in same-store sales for the quarter.