U.S. Treasury Secretary Paul O’Neill, bowing to criticism, said yesterday he will sell his estimated $90 million-plus stake in Alcoa, the aluminum giant he headed for 13 years. O’Neill made clear he wanted to avoid any perception of impropriety since President George W. Bush was drawing him into almost every issue that the government is involved in. Earlier, O’Neill had pledged to take no part in any policy discussions that might affect Alcoa — a tall order, since it is a $23 billion conglomerate with operations in 26 countries, dealing with aircraft and automakers, rail and shipping companies, among other interests around the globe. Wall Street was reluctant to criticize him outright, since few were willing to risk alienating such a powerful figure in the Bush administration, but there has been quiet support in the financial industry for a New York Times editorial, which earlier this month questioned O’Neill’s decision to keep the Alcoa shares.