NEW YORK, Sept 15 (Reuters) - NYSE Group Inc. (NYX.N: Quote, Profile, Research) will adjust trading fees on its electronic NYSE Arca trading system, trimming costs for trades sent with specific price instructions and raising fees for those without price limits, the Wall Street Journal reported on Friday. Under the changes, effective Oct. 1, NYSE Arca will charge 30 cents per 100 shares for orders without price instructions, tripling the old fee. Meanwhile orders with price limits now will get a rebate of 20 cents per 100 shares, the paper said. The changes do not affect New York Stock Exchange floor trades. The moves come as the NYSE, which merged with electronic stock market operator Archipelago earlier this year, tries to recover market share lost to archrival Nasdaq Stock Market Inc. (NDAQ.O: Quote, Profile, Research) and other electronic networks. The rebate for price-limit orders is designed to attract more rapid-trading investors to the system. Â© Reuters 2006. All Rights Reserved.