Note: some of the firms below adjust their salary in January following mass call in August by $500-$1k. International firms usually increase during the end of their financial year on June 30.
I also do not think some of the big four figures are correct. Most ranges from 5.3k to 5.8k. For small firm, they will usually pay 4.5k at the minimum because under employment act, if you pay someone below 4.5k, you have to compensate them for OT work. If you pay above 4.5k, your associate can do as much OT work as you require him/her to do without having to pay additional OT allowance. That is why most law firms in Singapore will pay a minimum of 4.5k unless they do not do OT at all.