There are no hard and fast rules. Depends on the creditor's policies. I think it is one of the factors but how much it is weighed depends on how strong your report is in other ways. From reports on forums such as fatwallet and creditboards, some have reported that Citi balks when they see 6 inquiries within the last six months on the report they pull, others have not had that problem. Some have reported that Nordstrom and Penfed balk at more than 4 in the last six months, others report no problem. It's a big YMMV thing.