India's National Stock Exchange (NSE) on Tuesday said it halved the lot size for trading derivatives contracts for the blue-chip Nifty 50 index to 25, and reduced the lot sizes for two other indexes as part of its periodic revision.

The move comes at a time Indian benchmark indexes have been hitting fresh record highs and seeing increased investor interest in trading derivatives.

The exchange operator reduced the market lot for the Nifty financial services index to 25 from 40 and Nifty midcap select index to 50 from 75, and kept the lot size for trading Nifty bank index unchanged.

The first monthly expiry contract with the revised lot size will expire on May 30 for the Nifty 50 index, while the first weekly expiry contract with revised lot size will expire on May 2, the NSE said in a circular.

Last week, the exchange operator revised lot sizes for some large-cap and mid-cap stocks in its periodic review.

(Reporting by Sethuraman NR and Nandan Mandayam in Bengaluru; Editing by Janane Venkatraman )