Exchanges require IPO applications in fixed bundles so that allotment can be processed fairly when demand is high.
When an issue is oversubscribed in the retail category, allotment is often done by a computerised lottery at one lot each. Applying for more lots does not always improve your odds in that situation.
An easy example
If the lot size is 53 shares and the upper price is Rs 282, one lot costs 53 x 282 = Rs 14,946. That is your minimum investment.
Important note
Retail applications are capped at an amount set by the regulator, currently Rs 2 lakh per application.
Common mistake
Applying for many lots in one retail application. Above the retail limit the application moves into a different category with different allotment rules.