The Frankfurt-based firm added that the USD 1.23-billion plan, still to be agreed at a supervisory board meeting on Friday, would see it report a loss in the third quarter as it writes down the value of goodwill and other intangible assets.
But it forecasts a "slightly positive" bottom line for the whole of 2016.
Like other German banks, Commerzbank is fighting headwinds from low interest rates in the eurozone, tough regulation, intense competition, and the arrival of new digital actors on the market.
"Profit volatility and risks from regulatory changes will be reduced and capital freed up for the core business" with the retreat from investment banking, the statement continued.
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To cover the costs of the restructuring, the bank said it would "cease dividend payments for the time being".
Commerzbank reported a profit of 1.06 billion euros in 2015, and paid its first dividend since the 2008 financial crisis at 20 cents per share.
Shares in the bank lost 0.77 percent to trade at 5.95 euros by 0945 GMT in Frankfurt, while the DAX 30 index of leading firms gained 0.69 percent.
Managers predict that the restructuring will create savings of 6.5 billion euros per year and allow them to create 2,300 new jobs in "growth areas" at the bank.
The German state remains a shareholder in Commerzbank to the tune of 15 percent after coming to the lender's rescue in 2008.
Chief executive Martin Zielke in August batted away rumours that he was considering a tie-up with Deutsche Bank, Germany's biggest lender and Commerzbank's historic Frankfurt rival.
The once-proud institution is labouring under a burden of around 8,000 legal cases worldwide including a USD 14-billion demand from the US Department of Justice over its activities leading up to the subprime mortgage crisis.