There are 2 Allocation Methodologies 1. Price Priority: Price Priority is a stock allocation method where preference is given to the highest price bidder. It's also called multiple clearing price as every bidder over clearing price gets allocation (based on price priority) 2. Proportionate Basis: Unlike Price Priority where allocation is done on multiple prices here allocation is done on a single price. Every buyer who has bid above or equal to the clearing price gets allocated on a proportionate basis. Note: Other than mutual funds and insurance companies no single bidder shall be allocated more than 25% of the size of OFS.
For more info: https://www.bseindia.com/downloads/faqforinvestors.pdf