Inverse ETF doesn't exist in India yet, there are NSE instruments traded in other overseas mkts though.
This whole concept comes from the restrictions of short selling cash mkt with carry ( mis works anyway).
In USA, naked shorting was allowed, but post 2008, even they changed a lot of rules.
Recently, some more developments have occured that is SLB
https://www.nseindia.com/products/content/equities/slbs/slbs.htm
Z also has an article on it:
https://zerodha.com/z-connect/queries/stock-and-fo-queries/basics-on-slb-stock-lending-borrowing
They also very recently, this year in 2019, got into it.
From the above docs, you can see that its still quite expensive to short sell. You need to pay everyone in the chain fees.
What they're trying to do, is to pool as many ppl into it by allowing them to lend the securities in their demat.
ETFs also afaik have to replicate whatever it says by holding the same underlying. Its not OI, but actual holding.
Since cost of shorting by borrowing is still high, inverse ETFs, will be pretty expensive and therefore not being considered to launch.
If the number of perma-bears really increases, it may workout one day
There is an SLB watch on NSE
https://nseindia.com/live_market/dynaContent/live_analysis/slbs_chain/chainDataBySeries.jsp
Actual costs, I didn't get the exact % or typical values. You can contact your broker.
1. Margin of borrowing is 125% with MTM like futures( margin call ) . After shorting, you'll release 100% but still need full 125% of cash upfront
2. commission paid to borrower + intermediaries
It isn't clear, maybe gst only on commission, but there is no STT, stamp duty and other overheads in borrowing/lending.
The short-seller will anyway pay STT etc when transacting with the new buyer, hence, no double taxation.
