The transaction is facing opposition from its top shareholder Freenet. Sources told Reuters last week that at least two other big investors were also against the 6.3 billion Swiss franc (5.3 billion pounds) deal.
"ValueTrust has reviewed the key performance indicators and financial projections of UPC Switzerland, its current trading as well as synergies emerging from the combination of UPC Switzerland and Sunrise," Sunrise said in a statement.
The Swiss telecoms firm said ValueTrust supported the financial terms of the transaction and standalone valuation of UPC Switzerland.
"Adjusted for cost and capex run-rate synergies, the operating free cash flow multiple based on the acquisition value of 6.3 billion Swiss francs (5.3 billion pounds) is 10.2 times for 2018 and 12.5 times for 2019, which are below the current trading levels of key listed peers," Sunrise said.
Sunrise said it would publish the full fairness opinion along with the invitation to the extraordinary shareholder meeting for investors to vote on the capital hike to help finance the deal that Freenet opposes.
(Reporting by Silke Koltrowitz; Editing by Edmund Blair)