The Dow Jones Industrial Average (DJI - 13,013.30) is down 12 points, or 0.1%, erasing earlier gains triggered by upbeat data out of China. Instead, investors are focusing on the Institute for Supply Management's (ISM) manufacturing index, which arrived at 49.5 in November -- down from October's reading of 51.7. This latest figure disappointed economists, who were expecting a smaller decrease to 51.0. Elsewhere, the CBOE Market Volatility Index (VIX - 16.22) is 0.4 point, or 2.2%, higher.

Here are a few noteworthy stats at midday:

1. The equity put/call volume ratio across all 10 options exchanges sits at 0.78, with 2.9 million calls exchanged so far today, compared to 2.2 million puts.
   
   
2. Among the equities with call-heavy activity is Allscripts Healthcare Solutions Inc (NASDAQ:MDRX – 11.15), which is up about 0.2% today. Currently, calls account for 97.8% of the stock's intraday option volume as speculators wager on potential merger rumors.
   
   
3. The put/call volume ratio on the iPath S&P 500 VIX Short-Term Futures ETN (NYSEARCA:VXX - 29.65) -- which touched a new all-time low of $28.81 earlier in the session -- stands at 0.86, with calls outnumbering puts.
   
   
4. The Nasdaq shows an advance/decline ratio of 0.91, with the number of downward movers outpacing the advancers.
   
   
5. Among the Nasdaq's major decliners is QLogic Corporation (NASDAQ:QLGC - 8.73), which has shed around 8% -- and tagged a new multi-year low of $8.63 -- in intraday action, after receiving some bearish analyst attention ahead of the open.