MTF collateral is the stock, ETF or mutual fund holdings used as collateral to get funding from your broker. An MTF collateral amount is a form of loan against shares offered by a broker to their clients for trading in stocks. 

The equity collateral margin is the amount obtained from pledged stocks, ETFs, and mutual funds, after accounting for the haircut deduction. In simple words, when you place your securities as collateral, your broker will deduct a haircut on the value of each security and give you the rest of the amount as loan, which you can use to trade in stocks or F&O.