NRG Energy (NRG, news, chart) is seeing 11 times its normal trading volume on increasing interest in September 40 calls. The stock is up $1.35 to $35.92 after the company reported second quarter results that trailed analyst forecasts, but also raised annual EBITDA guidance to $2.3 billion from $2.16 billion. In the options market, 79,000 NRG calls have traded, compared to 4,700 puts. Much of that volume is in the September 40s, where two blocks of 35,525 contracts traded bidside in afternoon trading. Total volume in that contract is now 71,197, compared to open interest of 17,110. It appeas that some of that activity might be tied to some buy writes, as two blocks totalling 4.4 million NRG shares traded within minutes of the options trades. If so, the strategist might be long the shares and looking to lower the cost basis of owning the stock by selling some September calls.