After raising his objections against Goods and Services Tax Network (GSTN), a private company, with Prime Minister Narendra Modi, BJP MP Subramanian Swamy on Saturday said he will now write to party president Amit Shah and chief ministers of BJP-ruled states to oppose it."I am writing to Amit Shahji and all BJP CMs that while ratifying the Constitutional Amendments for GST Bill, they should oppose GSTN," he twitted.The GSTN was incorporated in March 2013 by the then United Progressive Alliance (UPA) government with 49 per cent government share and 51 per cent private shares to manage the accounting and collection of GST.So far, eight states have ratified the GST Constitutional Amendment Bill. These include 5 BJP-ruled states -- Assam, Chhattisgarh, Jharkhand, Gujarat and Madhya Pradesh. On August 11, Swamy wrote to the Prime Minister to "have a close second look" in the matter."Being a Section 25 company, GSTN is a not-for-profit organisation. Then why should private profit making entities have any stake, and that too majority stake in it? What is in it for them," he had asked.