Manipal Health Enterprises Pvt. is planning to file for a $1 billion initial public offering in January, according to people familiar with the matter, setting the stage for the biggest such listing by a hospital operator in India.The company is targeting a valuation of as much as$13 billion, the people said, asking not to be identified because the information is private. The IPO will comprise a fresh issue of shares as well as an offer for sale by existing investors, they said, adding that final details ma ...