The Swiss newspaper Tages-Anzeiger reports that UBS is considering the move as looks to expand into Germany.
Commerzbank's investment banking operations currently employ around 900 staff and UBS is already looking to hire 1,000 new members of staff in Germany, even if a deal with Commerzbank does not bear fruit.
UBS spokeswoman told Reuters: "It's true that UBS wants to grow in Germany and we have new sites planned."
Meanwhile, Commerzbank's Klaus-Peter Mueller told Der Spiegel that the Swiss bank would be interested in buying SEB's German banking operations to boost its German presence, if the Swedes were willing to sell.