Aeroflex Holding Corp., the parent company of test equipment manufacturer Aeroflex Inc., said last week it has filed a registration statement with the U.S. Securities and Exchange Commission relating to the proposed $500 million initial public offering (IPO) of its common stock. Aeroflex, based in Plainview, N.Y., said it plans to trade on the New York Stock Exchange under the symbol ”ARX.” It was a public company for 46 years before private equity firms Veritas Capital, Golden Gate and a division of Goldman Sachs bought it in 2007.