11. Is there a ban on donations from corporations with partial government ownership to political parties?

While there is no ceiling on private contributions from individuals or legal entities, most parties met with by the OSCE/ODIHR NAM stated that they will rely mostly on public funds.
Source: OSCE/ODIHR (2016), Republic of San Marino, Early Parliamentary Elections, 20 November 2016, OSCE/ODIHR Needs Assessment Mission Report, OSCE/ODIHR, Warsaw

There is no ceiling on private contributions to political parties, or on how much the latter can raise from private sources.
Source: GRECO (2016), Third Evaluation Round, Evaluation Report on San Marino, Transparency of Party Funding, (Theme II), GRECO, Strasbourg