Steven Cameron, pensions director at Aegon UK, said there has been a lot of speculation over possible changes to pensions, but most rumours are unlikely to happen.
Elements of pension tax relief, salary sacrifice schemes and the long-standing 25% tax-free lump sum could be reviewed as part of an effort to close a £22bn funding gap.
40% of SMEs have made or considered changes ahead of the Budget, with 32% already cutting costs or restructuring and 31% delaying hiring.
In its Budget submission, the group warned that making changes just to fix short-term problems could damage trust in pensions.
Tania Bowers, global public policy director at APSCo, said: “This Budget is an opportunity to deliver meaningful reform that empowers employers and workers alike.”