If a sole owner has more than one business, and each operates
its own PAYE scheme, you have look at the individual circumstances
and decide if you can treat them as separate businesses for SMP
purposes.
Consider in these types of cases whether:
If the answers to these questions indicate that they are
separate businesses, then the owner would need to total the Class 1
NICs liability in the qualifying tax year for each business to see
if they qualified for SER. See
SPM21300
Alternatively, if the answers indicate that each business is
an integral part of the employer’s trade as a whole then the
employer may be less likely to qualify for SER. This is because
they would need to calculate the total Class 1 NICs liability in
the qualifying tax year for all the businesses. See
SPM21300.