* Q4 net loss 720 mln euros, worse than analyst forecasts
* Takes 560 mln euros writedown on tax accruals
* To book 500 mln euro restructuring charge in Q1 2013
* Shares down 4.8 pct, lagging sector index (Adds analyst, background)
By Arno Schuetze and Edward Taylor
FRANKFURT, Feb 4 Commerzbank posted a worse-than-expected quarterly loss on Monday that was saddled by heavy writedowns and said more charges would follow as it slashes up to 6,000 jobs.
Germany's second-biggest bank revealed a fourth-quarter net loss of 720 million euros, much worse than the 295 million expected. Coming just months after Commerzbank cut its medium-term profit forecasts, to the detriment of its tax bill, Monday's announcement sent the bank's shares tumbling.
"The negative trend of earnings disappointments continues," DZ Bank analyst Christoph Bast said, adding the large amount of writedowns was a surprise.
In November Commerzbank lowered its 2016 return on equity (RoE) target to roughly 8 percent at group level, setting a goal below the industry's average cost of capital of 10-12 percent.
As a result the bank is now unable to make full use of losses carried forward to reduce its tax bill and had to write down 560 million on deferred tax assets for the fourth quarter.
The lender also booked charges of 185 million euros related to the sale of its Ukrainian Bank Forum unit and by end-2012 increased provisions for bad loans by 21 percent to 1.7 billion.
By 1436 GMT the bank's shares were down 5.6 percent, easily outstripping declines in the overall sector
Commerzbank, which received an 18 billion-euro ($24.7 bln) government bailout at the height of the financial crisis, also warned that more charges are yet to come.
The lender will take a hit of around half a billion euros in the first quarter of 2013 in connection with its move to cut 4,000 to 6,000 jobs by 2016.
Commerzbank's announcement came just days after quarterly losses at bellwether Deutsche Bank plunged to their worst in four years, burdened by nearly 3 billion euros in one-off costs aimed at drawing a line under a slew of scandals.
However Commerzbank said it still expected to be able to pay, for the first time since the state bailout in 2008, the coupon on the government's loan. Called the "silent participation" the debt-equity hybrid was set up as a way for the bank to pay the government back and avoid a state stakeholding of some 80 percent. It is 25 percent state-owned.
Commerzbank is not required to service the state's silent participation as long as it posts a loss under German accounting standards.
The bank did not disclose its net profit result under German GAAP, but it broke even last year under international accounting standards.
Commerzbank posted a net profit of 6 million euros in 2012, down from 638 million in the previous year, with extraordinary charges totalling 980 million.
Operating profit came in at 1.2 billion, less than the 1.3 billion booked in the first nine months and by far off the original 2012 target of 4 billion euros.
Commerzbank is set to publish detailed financial results on 15 February. ($1 = 0.7301 euros) (Reporting by Arno Schuetze; Editing by Mark Potter and Sophie Walker)