By Jud Pyle, CFA, chief investment strategist for the Options News NetworkFinancial services provider Charles Schwab ( SCHW) is scheduled to announce second-quarter earnings the week of July 13. No firm date has been set but it's likely that the report will hit the Street on July 16 or 17, putting the announcement prior to the July expiration. Today, at least one investor boosted call volume by buying July calls and selling August calls. Amid a slow options trading day today, we noticed an investor bought approximately 10,000 July 18 calls and simultaneously sold 10,000 Aug. 18 calls with the stock at $17.03. The July 18 calls are currently trading up three cents and are home to current open interest of nearly 17,000 contracts. The Aug. 18 calls have gained five cents on the day so far, and are home to current open interest of 1,871 contracts. The volume weighted average price of the July 18 call is $0.209 per contract and August 18 call contracts are trading at $0.446. So the investor collected roughly 25 cents to buy July and sell August. This computes to an implied volatility of 38.1 for the August calls, compared to a 63-day realized volatility of 55. In light of the fact that open interest in the July 18 calls is close to the today's volume, it is likely that this is the same investor that sold 10,000 July 18 calls for around $1.25 with the stock at $18 back on May 19. We will know for certain when we see the open interest data for the July 18 calls. If the investor sold to close in July, we could see open interest fall by close to 10,000 contracts.