@Chhattisgarh , QIB subscription shows the institutional appetite for the IPO.
Look at SBFC's figures yesterday mcap - 6500 Cr. but QIB subscribed for more than 42k crores. This shows that there is huge institutional appetite for this IPO, which eventually decides listing.
Now, as per your argument QIB's shouldn't subscribed worth 42k in SBFC as Mcap is just 6500 Cr.
IMO, QIB subscription in no way depends on the Mcap company is trying to command.
It depends on the issue size and the their hunger for the shares.