Arrests were part of a joint operation involving Derbyshire and Nottinghamshire police, The Pensions Regulator and the Employment Agency Standards Inspectorate.
Three men aged 28, 37 and 38 and a 31-year-old women were arrested at a business premises in Derby city centre.
A 31-year-old woman was arrested after voluntarily attending a police station in Derby and a 35-year-old man was arrested at a business address in Nottingham city centre.
All were arrested on suspicion of fraud.
The searches and arrests are part of an ongoing criminal investigation into allegations of fraud relating to the automatic enrolment of staff into workplace pensions and underpaying workers.
Back in July, The Pensions Regulator reported two thirds of pension scheme members only know a little about pension scams, while just 3 per cent of industry experts had never heard of them.
According to the TPR’s latest ‘perceptions report’, 13 per cent of scheme members felt they were not aware of pension scams at all.
However, the TPR report revealed that a fifth of relevant audiences - trustees, in-house administrators, pension scheme managers and third party administrators - have experienced pension scams, with this figure being higher among large schemes.