Shares of Ruchi Soya tanked nearly 20% in early trade after the board of the Baba Ramdev-led firm cleared the allotment of 6.61 crore equity shares via a Follow on Public Offer (FPO). The firm plans to raise Rs 4,300 crore from the share sale. Ruchi Soya stock opened 19.36% lower at Rs 706 against the previous close of Rs 875.45 on BSE.