The Securities and Exchange Board of India announced a string of measures to bolster the primary market that is likely to encourage retail investor participation.

Sebi shortened the maximum time span between the closure of an issue and its listing from 15 days to six days.

The market regulator also changed the definition of `retail investor,' in the case of book-built issues, in favour of the amount invested rather than the number of shares applied for.

The green-shoe option in the issuance process has been made mandatory. This will ensure that in the event of over subscription, there is a mechanism for allotting extra shares, thereby curbing excessive post-listing price volatility of the newly issued shares.

Sebi also tightened norms for issuers to keep fly-by-night operators at bay.

(Sebi Chairman G N Bajpai speaking at a meeting in Mumbai).