Take context from the input text and decide on the accurate relationship between 'Xstrata' and 'Glencore' from the options provided.
Options: platform, distributed by, owned by, operator

Glencore took a $US7.7 billion write-down in 2013 on the $US29 billion "merger" with Xstrata it executed the same year, with the bulk of that taken on goodwill.
owned by