D6a26 - Is an employer required to supplement the pecuniary sickness allowance if his employee’s wage is higher than five times the social minimum wage?

Yes.

An employer who does not terminate the employee’s employment contract after a period of 26 weeks (duration of protection) is required to supplement the pecuniary sickness allowance or the payment made to him in order to bring it up to the net wage of his employee no later than 12 months following the month in which his incapacity for work occurred.