A newly published Sigma patent discloses the optical design of a 45mm f/1.2 MFT lens. If you compare the patent design (image on top) with the actual Olympus 45mm f/1.2 PRO lens design you will see they perfectly match.
This isn’t the first time we found a Sigma patent having the Olympus lens design. We also published the Sigma 8mm PRO lens patent here. And also Panasonic makes use of Sigma designs (see 12mm f/1.4 patent).
It means Sigma is the secret king in the MFT lens world :)