Foreign source income is totally exempt from Cantonal tax. Swiss taxes are deductible from the net income. Zug Income tax Incentives apply for domiciliary companies with neither premises nor staff. For domiciliary companies, there is a minimum amount. Holding companies Dividend income is for purposes of Federal income tax is subject to income tax in the hands of the recipient.
Many Cantons grant similar reductions for dividends.
This needs to be agreed with the Swiss tax authorities who usually limit the amount of other expenses and require payment of regular and substantial dividends.