Swiss lender UBS saw a 16% drop in its third-quarter net profit, compared to the same period last year, and a 59% slump at its investment banking unit amid a "challenging environment."

The bank's net profit attributable to shareholders for the third quarter came in at $1.049 billion. This is lower than the $1.253 billion figure reported in the same quarter in 2018.

Here are some key highlights for the quarter:

Operating income hit $7 billion, versus $7.5 billion a year ago.

Return on tangible equity stood at 8.7%, versus 11.1% a year ago.

Common equity tier 1 capital ratio of 13.1%, versus 13.5% a year ago.

UBS also said it expects to take restructuring expenses of $100 million in the fourth quarter of 2019. UBS, like its peers, is looking at ways to restructure as banks continue to face headwinds from low and negative interest rates.

"Low and persistent negative interest rates and expectations of further monetary easing will adversely affect net interest income compared with last year," UBS said in a statement Tuesday. "As we execute on our strategy, we are balancing investments for growth while managing for efficiency," it added.

Rising rates are good for banks since they are able to lend out money to investors at a profitable rate of interest. Lower interest rates restrict a bank's ability to make profits thus adding pressure on margins.

UBS announced in August that it would introduce a 0.6% annual charge on cash savings of over 500,000 euros ($557,642) and 0.75% on savings of over 2 million Swiss francs ($2.03 million) in order to pass on the cost of negative rates.

Speaking to CNBC Tuesday, CEO Sergio Ermotti said: "The entire industry is faced with the same challenge on negative rates, so we are unfortunately forced to pass some of this pain, so we are not really passing all the pain of negative rates but I think it is inevitable that we will see, probably, the rest of the industry following on that."