The Nifty 50 companies lost Rs 4 lakh crore market cap on Thursday due to SEBI's F&O curbs and Middle East tensions.Nifty Futures rolled over 76.27% of positions to the June contract, starting with an open interest of Rs 37,265 crore.There is significant Call writing between 24,800 and 25,000 levels, with total Call open interest acting as resistance at 25,000.Foreign investors are cautious in the June contract, with a higher proportion of short positions and a decline in long positions.