New Delhi, Oct. 29 -- Indian traders are growing wary, with the Nifty's rollover cost sinking to a five-month low at the expiry of the October series as high oil prices and the threat of renewed US-Iran hostilities dull their appetite for fresh bets.

The cost fell to 0.29% in October from 0.78% at the end of the September series, according to an Aditya Birla Money Ltd report. It was the lowest since the May expiry, when traders were similarly worried about a fragile ceasefire in West Asia, said Shai Coelho, founder of online analytics platform Vtrender.

Rollover cost is the price traders pay to carry forward an expiring futures position into the next contract. It is measured by the premium or discount of the next-month contract to the e...