	In 2005, together with a partner, he founded the "four-quarters group", whose managing director and principal shareholder he is. The start-up consulting company of the group now operates under the name "four-quarters EXIST GmbH". Since 2008, Roski has also been a founder and managing director of "IKSOR GmbH" (Family Office & Business Angel) and since 2012 authorized representative of "mein-mikrofinanzierer GmbH", a state-accredited microfinance institution.