Avaya Holding Corp. filed for a $1 billion initial public offering, according to a Securities and Exchange Commission filing Thursday. Silver Lake Funds and TPG Funds own about 72.3% of the company’s 487.4 million outstanding shares. The IPO would value the telecom equipment maker at just over $5 billion. Joint book-runners for the offering include Morgan Stanley, Goldman Sachs, J.P. Morgan, Citigroup, Deutsche Bank, B. of A. Merrill Lynch, Barclays Capital, UBS and Credit Suisse.