The three are Alan Venn former regional director of Howard Smith's southern division, Andy Thompson former regional director of its Midlands division and Tony Wood former regional director for the London division.
Former Howard Smith Paper London salesman Andrew Harding has also moved to Premier.
When their departure was revealed last week their destination and identity was not revealed secrecy for legal reasons.
They join former Howard Smith chief executive Martyn Eustace and managing director Fred Haines at the rival merchant group.
Both left the Northampton-based merchant, part of PaperlinX, in May this year. And have been joined in the Map Merchant organisation by Stephen Paul, former managing director of Howard Smith Paper (Scotland).
Story by Andy Scott