The largest alternative investment firm in the world, Blackstone specializes in private equity, credit and hedge fund investment strategies, as well as mergers and acquisitions (M&A), restructurings and reorganizations, and private placements. Its portfolio companies employ more than 560,000 people across the globe. The New York City-based company has completed investments in such notable companies as Hilton Worldwide, Merlin Entertainments Group, Equity Office Properties, Republic Services, AlliedBarton, United Biscuits, Freescale Semiconductor, Vivint, and Travelport. Blackstone was founded in 1985 as a mergers and acquisitions boutique by Peter G. Peterson and Stephen A. Schwarzman. Blackstone is headquartered at 345 Park Avenue in Manhattan, New York City.