Deutsche Bank has warned investors it will post a net loss of €6.2bn (£4.5bn) for the third quarter.
Higher capital requirements for its investment bank were partly responsible for the huge impairment charges of €5.8bn.
There was also doubt about the value of its Postbank retail division that Deutsche plans to sell.
Germany's biggest bank also said the dividend for the year could be cut or scrapped.
The group was also setting aside €1.2bn for legal costs.
Deutsche is embroiled in the Libor-rigging scandal and is being investigated by Swiss authorities for suspected price-fixing on the precious metals market.
Analysts had expected a net profit of about €1bn for the third quarter before the unexpected announcement on Wednesday night.
The bank also wrote down by €600m the value of its 20% stake in Hua Xia Bank, which it also plans to sell as it was no longer considered to be strategic.
The writedowns would not affect Deutsche's capital ratio, which stands at an expected 11% for the third quarter when measured by the most stringent test that is part of new European bank rules.
New chief executive John Cryan, who took over in July, is preparing to cut about 23,000 jobs - about a quarter of the workforce - in a bid to reduce costs, it was reported last month.
Deutsche Bank is due to publish its full third-quarter results on 29 October.


Troubled supermarket Tesco has announced another big fall in profits as it struggles to turn its business around.
Underlying profits for the first half of its financial year were £354m, 55% down on the same period last year, when it made £779m.
Its pre-tax profit was £74m, compared with a loss of £19m for the same period a year ago.
Like-for-like sales were down 1.1% for the UK, but sales volume rose 1.4%.
The number of transactions were also up by 1.5%.
Chief executive Dave Lewis has put pressure on profits by focusing on price cuts and putting more staff in stores, in an effort to attract customers back to Tesco.
He told the BBC he was "quietly confident" about Tesco's turnaround, admitting the group hit a low point at the end of last year.
"We obviously had some issues to deal with, we dealt with them. It meant that in the second half of last year we made no profit whatsoever in the UK.
"So if I compare to the second half of last year, the first half of this year feels like we've made some progress," Mr Lewis said.
"Our sales are growing compared to where they were either a year ago, or indeed in the second half of last year. And we've generated some profit as we rebuild the profitability of Tesco business. But importantly at the same time, improving what it is we're doing for our customers."

'Hurdles to overcome'

Mike Dennis, of global financial services firm Cantor Fitzgerald Europe, described Tesco's interim results as "disappointing".
"The risk now is that Tesco's recovery needs more time, requires more restructuring and asset sales and, with less cash flow, could require a rights issue to lower the indebtedness," he said.
Charles Hanover, investments partner at Dafydd Davies, said: "Tesco did not have a great set of numbers, but they were marginally better than expected.
"In the medium term, it's still a strong business, but in the short term, they still have hurdles to overcome in terms of competition from cheaper rivals."
Tesco has confirmed it will cost it about £500m to meet the government's proposed National Living Wage rate of £9 an hour by 2020.
Mr Lewis said the group already paid more than the £7.20 minimum which is being brought in under the National Living Wage plans next April.
He added that extra staff benefits already brought its hourly rate closer to £9.
Tesco has completed the sale of its Homeplus stores in South Korea, reducing its debt by £4.2bn.
It has decided to keep its Dunnhumby data business which runs its Clubcard loyalty scheme, after failing to attract enough interest in its sale.
In April, Tesco reported the worst results in its history, with a record statutory pre-tax loss of £6.4bn for the year to the end of February.
The supermarket is still under a criminal investigation by the Serious Fraud Office (SFO) after it admitted overstating its profits by £326m nearly a year ago.
Mr Lewis declined to comment in a BBC interview on reports that the company was close to striking a deal with the SFO.


Shares in Japan were choppy on Thursday after official figures showed Japanese firms could be spending less on physical assets.
Core machinery orders, a leading indicator of capital expenditure, fell by 5.7% in August, compared with expectations for a rise of 3.2%.
Japan's Nikkei 225 index was down 0.49% at 18,234.04 points in mid morning trade.
Investors were also taking in fresh official trade numbers from August.
The country's ministry of finance said Japan posted a current account surplus for the 14th month in a row, but that exports were up 3.1% in August from a year earlier, compared to a rise of 7.6% in July.
The official numbers showed the surplus at 1.65tn yen ($13.8bn) against expectations for about 1.23tn yen.
Meanwhile, global investors were also absorbing a warning from the IMF which said "global financial stability is not yet assured".
A senior IMF official said the nature of the danger had changed. Financial stability in advanced economies has improved, but risks had moved towards emerging economies, Jose Vinals explained.

China reopens

As mainland Chinese markets reopened after the Golden Week holidays, the Shanghai Composite benchmark index was up 3.3% 3,153.46 in mid-morning trade.
However, Hong Kong's benchmark Hang Seng was down 0.66% at 22,366.48 points after marking its highest close since 20 August on Wednesday.
In Australia, the S&P/ASX 200 was up 0.42% at 5,219.90, with shares in mining giant BHP up 2.97%.
In South Korea, the Kospi index was flat, down 0.09% at 2,003.97.


SABMiller has rejected an improved offer from Anheuser-Busch InBev that it says "very substantially undervalues" the company.
AB InBev on Wednesday raised its offer for SAB to £42.15 a share, having previously bid £38 and £40.
SABMiller closed up 2.4% at £37.08, having risen sharply since InBev first made its move last month.
Any deal between the two would create the world's biggest brewer, worth more than £180bn.
SABMiller said its board had formally considered the new offer, and had "unanimously rejected the proposal as it still very substantially undervalues SABMiller, its unique and unmatched footprint, and its standalone prospects".
AB InBev brews Budweiser, Stella Artois and Corona, while SAB brews Peroni and Grolsch, among others.
If a deal does go through, the merged company would produce one-third of the world's beer.
On Tuesday, SAB reported a 9% fall in revenues for the three months to September, which it blamed on weakening emerging market currencies.
Sales volumes were up 2%.
Shares in AB InBev closed up 0.6% in Brussels at €98.65.


(Close): Shares on Wall Street ended higher on Wednesday despite a fall in oil prices after official US data showed large stocks of crude.
The Dow Jones Industrial Average closed up 0.73% at 16,912.2 points.
The price of Brent crude rose as much as 0.8% to $52.73, but later settled at $51.33 a barrel.
All the other main US indexes made similar gains, with the S&P 500 closing up 0.8% at 1,995.8, while the Nasdaq finished 0.9% higher at 4,791.1.
Oil company Chevron was the biggest gainer on the Dow in early trading and ended the day up 1.3%.
The construction equipment maker Caterpillar rose nearly 2% in morning trade, but finished down 0.6%.
Its shares have fallen from about $115 since the beginning of the year after cutting its workforce.
On the wider S&P500, shares in Yum Brands, the owner of KFC and Taco Bell, ended the day down 18.8%.
The company lowered its full-year earnings forecasts, saying it had been hit by slow growth in China and the strength of the dollar.


Dozens of leading news organisations, including the BBC, are taking part in a scheme that will allow their web-based articles to load more quickly on smartphones and tablets.
Leaders of the Accelerated Mobile Pages (AMP) initiative promise that the stripped-back versions of the pages will be "lightning fast" to load.
The move has been led by Google, which is providing use of its servers.
Participants believe it may discourage the use of ad-blocking plug-ins.
AMP works by simplifying the technical underpinnings of the pages involved.
Much of the Javascript code used on normal webpages is absent, meaning articles should not only appear faster but use less battery power.
Publishers can continue to tap into the same ad networks as before, but they will not be able to display some types of adverts including pop-ups and "sticky" images that move as users scroll down a page.
Twitter, LinkedIn, Pinterest and Wordpress have said they also intend to make use of the technology.
Facebook is a notable exception. The social network recently launched an alternative programme called Instant Articles, which speeds up the delivery of third-party content by hosting it on its own platform.


Cache and serve

News sites will automatically create AMP versions of their stories at the same time as they publish and update the originals.
Google intends to scrape these from the web, store them on its cache servers and then serve them to users via its Search and News tools.
Likewise, the social networks involved are also expected to cache and direct users to the AMP articles rather than the originals if users click on relevant links in their apps.
"Today, roughly 40% of users abandon an article if it doesn't load after six seconds," Danny Bernstein, Google's director of product partnerships, told the BBC.
"To be able to pull down an article instantly from Twitter, from Pinterest is a remarkable thing.
"We'll support accelerated mobile pages in search in 2016, but the code is public, so publishers can launch them today, and we expect some smaller apps to be able to render AMP files immediately."


Shares in Yum Brands, which owns KFC and Pizza Hut, fell more than 17% in after-hours trading in the US after the firm reported poorer than expected results for the three months to 5 September.
Yum also lowered its full-year earnings growth forecast in its key market of China.
The firm blamed a stronger US currency against the yuan for its poor results.
But it also still recovering from a food scandal last year.
The group's KFC restaurants in China suffered in July last year after a television news story linked the brand to supplier Shanghai Husi Food, which was accused of selling meat that was out of date.
"The pace of recovery in our China Division is below our expectations," said Chief executive Greg Creed in a statement.
"While it remains difficult to forecast China sales, we are now estimating full-year same-store sales to be low single-digit negative," the firm said.
"Given a slower-than-expected recovery in China sales, particularly at Pizza Hut Casual Dining, as well as stronger foreign exchange headwinds, we now expect full-year EPS (earnings per share) growth to be low-single-digit positive."

Globally, Yum Brands reported third-quarter earnings per share growth of 14%, with adjusted third-quarter earnings of $1 (£0.65) a share and revenue of $3.43bn (£2.25bn).
Expectations were for earnings per share growth of $1.06 per share and revenue of $3.67bn.
"Outside of China, our Taco Bell and KFC Divisions continued to sustain their positive sales momentum," said Mr Creed, "while Pizza Hut was relatively flat."
"Given our lower full-year expectations in China, combined with additional foreign exchange impact, we now expect 2015 EPS growth to be well below our target of at least 10%."


Fifa president Sepp Blatter is facing a 90-day provisional suspension.
Members of Fifa's ethics committee have recommended the sanction after the Swiss attorney general opened criminal proceedings against the 79-year-old.
He is accused of signing a contract "unfavourable" to football's governing body and making a "disloyal payment" to Uefa president Michel Platini.
Blatter denies any wrongdoing and his lawyers said he had "not been notified of any action".
European football chief Platini - who wants to succeed Blatter - has said the payment was "valid compensation" from his time working under the Swiss more than nine years ago.
The investigatory chamber of Fifa's ethics committee has requested the ban and a final decision is likely to be made on Thursday by Hans Joachim Eckert, the head of Fifa's ethics adjudicatory chamber.
Blatter's adviser Klaus Stohlker said the Fifa president was "calm" after being told the news, but a statement from his legal representatives denied he had been made aware of any decision.
It said: "We would expect that the ethics committee would want to hear from the president and his counsel, and conduct a thorough review of the evidence, before making any recommendation to take disciplinary action."
On Wednesday, Blatter told a German magazine  he was being "condemned without there being any evidence for wrongdoing".
The investigation is centred on allegations believed to be around a 2005 TV rights deal between Fifa and Jack Warner, the former president of Concacaf, the governing body of football in North and Central America and the Caribbean.
The ethics committee had been meeting in Zurich since Monday and have yet to make a decision on Platini, 60.
It is also examining a payment of two million Swiss francs (£1.35m) that Platini received in 2011 for working for Blatter.
The Frenchman has provided information to the criminal investigation but said he has done so as a witness.
Swiss prosecutors said he is being treated as "in between a witness and an accused person" as they investigate corruption at world football's governing body.
The latest development came hours after former Fifa vice-president Chung Mong-joon, who is also under investigation by Fifa's ethics committee, told BBC Sport his campaign to succeed Blatter was being "smeared".
Blatter won a fifth consecutive Fifa presidential election on 29 May but, following claims of corruption, announced his decision to step down on 2 June. He is due to finish his term at a Fifa extraordinary congress on 26 February.


South Korean tech giant Samsung Electronics expects its third-quarter operating profit to beat market forecasts on the back of strong semiconductor sales.
It forecasts that operating profit jumped nearly 80% from a year ago to 7.3 trillion won ($6.29bn; £4.13bn).
The guidance figures for the three months to September exceeded analysts' expectations of about 6.8tn won.
The amount would mark the firm's first quarterly profit growth in two years.
The world's biggest smartphone maker has been facing stiff competition for its premium smartphones from rival Apple, while cheaper Chinese competitors such as Xiaomi continue to eat into its market share on the bottom end.
Analysts said stronger sales in its chip business and favourable currency exchange rates had offset the weakness in its mobile business.
Samsung is also the world's biggest maker of memory chips and its semiconductor unit is expected to be its top earner for the fifth consecutive quarter.
A weaker won has made the firm's products cheaper to buy overseas and helps boost its bottom line when it repatriates its earnings.
Samsung expects its sales to have risen by 7.5% to 51tn won in the same time period.
Seoul-listed shares of Samsung jumped nearly 9% after the positive earnings guidance.
The guidance release does not include a breakdown of results in its various divisions or a net income figure. Its final audited results are due out later this month.


Bryan Habana equalled Jonah Lomu's World Cup try-scoring record with a hat-trick as South Africa reached the quarter-finals by thrashing USA.
The winger scored three times in 21 second-half minutes to draw level with Lomu's mark of 15 World Cup tries.
The Springboks ran in eight second-half tries in all to earn a bonus-point win at the Olympic Stadium.
South Africa top Pool B and will now play the loser of Saturday's Pool A decider between Australia and Wales.

A tale of two halves

A mixture of South Africa's ill-discipline and poor finishing kept the score down in the first half, while USA only made it into the Boks' 22 in the last minute of the half, despite enjoying plenty of possession.
Centre Damien de Allende scored his first international try before South Africa were awarded a penalty try as USA struggled at the scrum.
A different South Africa came out after the break as Habana scored almost from the restart, collecting a Fourie du Preez kick to go over in the corner.
Bismarck du Plessis and Francois Louw both crossed the line, before Habana scored two tries in two minutes to complete his hat-trick.
Louw scored his second with Jesse Kriel also getting on the scoresheet, before Lwazi Mvovo rounded off a dominant Springboks performance.

Brilliant Habana

Habana had a subdued first half, with his only contribution of note seeing him clatter into Blaine Scully as the pair competed for a high ball.
But he came out firing in the second half and his hat-trick not only saw him equal New Zealand legend Lomu as the tournament's all-time leading try scorer, but also draw level with Australia's David Campese for joint second in the list of Test try scorers with 64.
The 32-year-old, a 2007 World Cup-winner with the Boks, scored 62 seconds into the second half for his 13th World Cup try.
He then went over unopposed in the 59th minute after a break by De Allende and swooped on a loose ball to dive over in the corner just two minutes later.
Habana could have broken All Black winger Lomu's record but a knock-on as he tried to collect another chip through denied him a fourth try on the night.


Wales are so close to qualifying for the Euro 2016 finals in France they can almost smell the croissants.
Manager Chris Coleman's men go into the final Group B qualifiers - away to Bosnia-Herzegovina in Zenica on 10 October and against Andorra, on 13 October - knowing just a point will guarantee them a place at a major finals for the first time since 1958.
Last month's 0-0 draw with Israel ruined the qualification party plans for that day in Cardiff but, after 57 years of waiting, another few weeks won't hurt...will it?

The wait goes on

Victory against Israel would have secured qualification and a sense of expectation engulfed the Cardiff City Stadium on a fair-weather day made for partying.
In the hours that followed the draw with Israel, there was another scenario so typical of Wales' footballing history, littered with near-misses.
Welsh fans had expectations lifted again as, with growing excitement, they watched Belgium toil to break down Cyprus in Nicosia.
If Cyprus had drawn or beaten Belgium, Wales would have qualified that day.
Again Wales' hopes were thwarted. Chelsea midfielder Eden Hazard scored with just four minutes to go to give Belgium a 1-0 win over Cyprus.
Some fans would have felt that this would have been an anticlimactic way to make it in any case. Captain Ashley Williams and his players probably would not have complained.


In the last week, there have been media reports questioning the future of the British Grand Prix and the announcement of a 21-race calendar for the 2016 season.
In combination with this weekend's stop on the schedule - the Russian Grand Prix - it is a reminder of the direction in which Formula 1 appears to be headed.
More of the historic European events that reflect the essence of racing are disappearing off the F1 schedule to be replaced by big state-funded projects that fail to deliver the same kind of racing and atmosphere.
That the F1 schedule is in a state of major flux is without doubt; whether that is necessarily a good thing is a different matter.

Does F1 need European races?

Europe is where F1's heart is - in terms of the teams, the drivers and its core audience. And yet the future of a number of countries as race holders is in doubt.
Silverstone has a contract to stage the British Grand Prix that lasts until 2026, with the first break clause after 2019, but that has not stoppedquestions about its future. 
Monza in Italy, the oldest race of them all, has one more year on its deal and there has so far been no agreement on the financial conditions for a new one.
Germany dropped off the calendar this year because of financial problems at the Nurburgring and there are doubts about its long-term future after a poor crowd at the other venue, Hockenheim, in 2014.
These are all circuits with a long and rich history. Nurburgring has held 40 grands prix; Hockenheim 34; Silverstone 49. Monza has been on the grand prix calendar almost uninterrupted since 1922.