What about the law?

When the public sector buys goods, services or construction contracts, it usually takes place through a public procurement. Public procurement is a legally regulated purchasing process that must ensure that public purchases are opened to competition and that public funds are used as efficiently as possible. Public procurement is regulated, among other things, by the Public Procurement Act (LOU). The rules for public procurement are based on EU directives. Directives are an important part of the work to promote free movement of goods and services within the EU. By following the Swedish procurement rules, procuring authorities and entities fulfill the obligations that follow from EU law.

Lag (2016:1145) om offentlig upphandling, Sveriges Riksdag