I think the fall is mostly due to the rights issue. Many have dumped their shares at higher price to buy shares through rights issue at lower price. Let us look at the calculation as per yesterday’s price
South Indian Bank was trading at around 28.8 yesterday
South Indian Bank RE (Rights Entitlement) was selling at 5 yesterday
Suppose you have 1000 shares. You sell those 1000 shares at 28.8. You get 28000
You buy 1000 RE shares at 5. Your outflow is 5000
These RE give you the rights to purchase shares at 22.
So you apply for 1000 shares in rights issue at 22. Your outflow is 22000
Your total outflow is 22000+5000 = 27000
Your inflow is 28800. You gain 1,800. Your final gain might be less after brokerages and transaction costs.