In a share deal the employer remains the same company.
In a share deal only the shares of the company change owner. The company itself remains the employer, the employment relationships continue unchanged. A transfer of business under AVRAG does not take place, the right of objection and the special protection against dismissal because of the transfer do not apply.
Nevertheless you should capture the existing employment relationships, pension commitments and severance entitlements in the review. How the forms of acquisition differ is shown in the post on share deal or asset deal.