Mammoth Mountain is owned by Alterra Mountain Company, a major ski resort operator formed by a partnership of Aspen Skiing Company and KSL Capital Partners. Mammoth Mountain itself is operated through Mammoth Resorts under the Alterra umbrella.

Current owner

  • Mammoth Mountain Ski Area’s parent company, Mammoth Resorts, was sold in 2017 to a joint venture of Aspen Skiing Company and KSL Capital Partners.
  • That venture was subsequently organized under what is now known as Alterra Mountain Company, which lists Mammoth Mountain among its portfolio of ski destinations.

How the ownership evolved

  • Founder Dave McCoy ran Mammoth for decades before selling a majority stake in 2005 to Starwood Capital Group for about $365 million.
  • In 2017, a Starwood affiliate agreed to sell Mammoth Resorts (including Mammoth Mountain, June, Bear, and Snow Summit) to the Aspen–KSL partnership, leading to its inclusion in Alterra’s multi-resort platform.

Practical takeaway for visitors

  • For guests, this ownership mainly shows up through shared pass products and investments in lifts, snowmaking, and base facilities under the broader Alterra network.
  • Day‑to‑day operations, branding, and local management still trade as Mammoth Mountain / Mammoth Resorts, even though strategic control sits with Alterra.

TL;DR: If you are asking “who owns Mammoth Mountain” today, the answer is Alterra Mountain Company via its Mammoth Resorts subsidiary.

Information gathered from public forums or data available on the internet and portrayed here.