Financial Times (behind a paywall) just published an article entitled "Daniel Loeb calls on Sony to sell sensors business." Loeb's Third Point, in a letter to investors today, according to the FT, publicly acknowledged it had built up a USD$1.5B stake in Sony. Loeb is apparently calling for Sony to hive off its sensors business, listing it in Japan as a separate company. Apparently, Loeb has set up a website laying out his thesis. Sony and Loeb previously tangled back in '13.
See also the related reports at Nikkei and Reuters.
Thanks Richard!