Domestic bourses will levy STT, or securities and transaction tax, on the ‘intrinsic value’ from September 1 instead of the settlement price used at present in the case of exercise of options, National Stock Exchange said in a circular on Tuesday.The intrinsic value is the difference between the settlement price and the strike price of the option. Finance Minister Nirmala Sitharaman has announced this change in her Budget speech on July 5, and the bourses have now notified the same for implementation with effect from September 1.STT is charged on every purchase or sale of listed securities, including shares, derivatives or equity-oriented mutual funds.Amit Gupta, CEO and Co-founder TradingBells said this would provide relief to traders as they won't have to be worried about compulsorily squaring off in-the-money options before expiry.STT was introduced in the Union Budget of 2004 and came into effect from October 1 that year. The STT rate differs based on the type of security traded and whether the transaction is a purchase or a sale.