In a question and answer session with DPreview Sigma’s CEO Kazuto Yamaki made it clear that their new strategy is to manufacture the lenses for FE mount camera and also exhaled that it may be either a F1.4, or something different” referring to the Sony 55mm f/1.8 lens:
A lens like Sony’s Zeiss 55mm F1.8 for the FE mount is optically superb but quite small and light. If you were to design ‘Art’ lenses for that system, would you try to strike a different balance between quality and size, and try to make the lenses smaller?
Yes – that’s also one of the segments we’re interested in. Another motivation for us to make new lenses is to differentiate between other manufacturers. Sony already has a 55mm F1.8 which is nicely sized and reasonably priced, so why make another? But F1.4 compared to F1.8 is a huge difference, so we’d either make a F1.4, or something different.