11,561 remains key resistance for Nifty

Option traders sold sizeable quantities of call and put options at the 11,500 strike intraday, which pegs the weekly Nifty range for the day at 11,359-11,641.

The 11,500 call expiring on September 17 had the highest open interest of 34.14 lakh shares (75 shares make one contract) intraday Tuesday, implying that 11,561.5 remains a key resistance for Nifty.

The weekly put with the highest OI remained 11,400 intraday.

The intraday value of the weekly 11,500 straddle call and put was Rs 141 a share intraday. The option sellers make money so long as Nifty remains within the 11,359-11,641 range.

Siemens, Idea and Titan saw the highest spurts in open interest intraday Tuesday.