Cisco Systems (CSCO) saw a notable increase in open interest after a day of active trading yesterday. Shares finished down 2.5 percent to $21.13 and the top trade of the day was a block of 18K Sep 22 calls at the 37 cent ask price. Open interest in the contract increased by 21K and so this looks like an opening buyer. Meanwhile, another strategist bought-to-open the Sep 21 straddle at $1.37, 15000X. In all, open interest incrased by 40K in CSCO calls and 29K in CSCO puts. Implied volatility rose by 10 percent to 32, as some players in the options market appear to be bracing for a larger price swing in shares of the tech bellwether. Shares are down 13 cents to $21 this morning and IV up to 33.

3PAR (PAR) is up 70 cents to $26.79 and options volume is running 21X the average daily on speculation DELL might make a counter-bid for the storage device maker. H-P made a move to buy the company yesterday at a 33 percent premium over Dell Computer’s initial offer. PAR is up and it looks like some investors are indeed bracing for a sweetened Dell bid, as Sep and October 30 calls are seeing heavy trading and implied volatility is up 28 percent to 36.5.

*Scanning all single-stocks subject to 2500 contracts minimum call or put volume

Monster Worldwide, the online job posting site, is down 30c to $10.30 a new 52-week low and option volume is 23x the daily average driven by in the September $10 puts in which block of 9,800 (total 11,000 contracts) have traded against prior open interest of just 964 in the strike. This is appears to be an opening sale and would consistent with a theme that developed yesterday as we saw put selling in names such as WAG, SVU, SWY, HSY as the stocks sank lower. The difference here is that Monster would be considered a very economically sensitive company whereas the others are viewed as defensive for a slowing economy. Today’s action is not a positive response to the news that MWW has finalized a deal to acquire HotJobs and entered an agreement with Yahoo.

Cemex, the Mexico based cement firm, dips 35c to $7.80, a new 52-weeek low following weak housing data. Notable trade as the September $7 put and $8 call each trading 5,000 contracts in what appears to be a bearish risk/reversal (bought puts and sold calls ) for a 3x net credit. While OI in the puts is sufficient to cover tis appears to be an opening position. Also notable was the Jan $10 calls saw the purchase of a 2,500 contracts at 29c in what looks like new position. This could be one strategist position positioning for continued short-term weakness but with expectations of 4th quarter pickup.

*Scanning all single-stocks subject to 2500 contracts minimum call or put volume

Akamai (AKAM) is down $1.16 to $45.57 and the Sep 45 – 47 put spread is sold at $1.14, 10000X. It likely rolls down in strikes, closing (for $3.25) a position in the Sep 47 puts opened Friday at $2.21 per contract — see 8/20 color.