* Investors had expected a profit in Q3, CEO says

* CEO says bank will continue to move forward

* Adds turning UBS around would not just take a few months

ZURICH, Nov 5 (Reuters) - UBS (UBSN.VX: Quote, Profile, Research)(UBS.N: Quote, Profile, Research) chief Oswald Gruebel said in a memo that quarterly results showed the bank had made good progress despite a quarterly net loss, but warned that rebuilding the bank would take more than just a few months. On Tuesday the Swiss bank posted a higher-than-expected third-quarter net loss and large client withdrawals at its core wealth management division, triggering a fall in shares. [ID:nL2713325] But taking out one-off charges, UBS was able to improve its operating profit.

"We have made good progress until now, which makes me optimistic. I am confident we will continue to move forward," Gruebel said in a memo to employees.

UBS was forced to make more than $50 billion of writedowns on bets it made on risky investment assets and was also caught up in a high-profile U.S. tax fraud row, which it has now resolved.

Gruebel, who was pulled out of retirement in February to restructure the bank, said the fall in shares on Tuesday indicated investors had been hoping for a profit.

But turning around UBS would take time and discipline, he added.

"We do not want to shine in the short term by producing a few good numbers. Rather, we are working to create a new and sustainably profitable UBS, a firm that will never again make the same mistakes it did in recent years," he said.

"That cannot be achieved in a few months. It takes more time because a lot needs to be changed." (Writing by Lisa Jucca, editing by Will Waterman)