(Adds fresh quotes, details)

By Natsuko Waki

LONDON, Feb 11 (Reuters) - The Kazakh tenge lost almost a fifth of its value on Wednesday after the central bank devalued it, taking the wind out of the sails of speculators and weighing on other regional currencies including Ukraine's hryvnia.

The Nigerian naira hit a two-year low against the dollar as weakening global commodity demand raised concerns about the country's economic outlook and the ability of the central bank to support the currency in the face of falling reserves.

Benchmark emerging stocks bounced higher, helping currencies with heavy reliance on external capital, such as the Turkish lira and South African rand, which have been under heavy selling pressure in recent weeks.

The tenge traded at 186 per dollar KZT= after the central bank said it would devalue the currency by 19 percent because of a decline in other emerging market currencies and to try to prevent large-scale market speculation.

"Given the pressure we have seen in emerging markets and the pressure on the rouble, the downward pressure on commodity prices from a slowdown in Chinese growth, this had to happen," said Lars Christensen, chief emerging market strategist at Danske Bank.

"If they had not devalued, there would have been serious problems for the Kazakh economy."

The devaluation lifted Kazakh stocks, with the local market

.KASE rallying 12 percent. London-listed Kazakhmys KAZ.L jumped more than 25 percent.

Many ex-Soviet Union countries are under pressure to contain a spillover from a sharp fall in the currency of their main trade partner Russia. The rouble has fallen 5 percent against the dollar this year because of concerns over the country's slowing economic growth and high inflation.

The rouble eased 0.2 percent to the dollar RUB= before erasing losses.

Ukraine, where anti-government protests are weighing on the economy, last week imposed new capital controls to support the hryvnia. But in the week prior to that the central bank had allowed the currency to depreciate.

The hryvnia was down 1.9 percent on the day at 8.57 per dollar UAH= , having fallen as low as 8.87 last week, levels not seen since September 2009. Banks said capital controls were likely to cripple trade and lead to a currency black market.

The naira hit a fresh two-year low of 164.85 per dollar

NGN= .

Oil-rich Nigeria's central bank announced new rules on Friday requiring currency dealers to put naira in their accounts at the bank two days before bidding in its forex auctions.

Nigeria has been selling dollars directly to lenders to prop up the naira, which has lost 2.9 percent this year as the U.S. Federal Reserve started withdrawing monetary stimulus, leading offshore investors to pull money out of local bonds.

"Commodity exporters, with the exception of pegged currencies - most are falling. It's a catch-up with what's happened elsewhere," Christensen said.

A weaker currency worsens the inflation outlook as Nigeria depends on imports for almost 80 percent of goods sold in the country.

Nigeria's foreign reserves fell 7 percent to $42.69 billion in February from a year earlier, raising doubts over the ability of the central bank to support the currency.

The benchmark MSCI emerging equity index was up 0.7 percent

.MSCIEF as investors looked to Fed chair Janet Yellen to clarify uncertainties about the central bank's plan to withdraw stimulus but support the recovering U.S. economy.

The lira was up 0.7 percent at 2.20 per dollar TRY= and the rand added 1.8 percent to 10.98 ZAR= . Emerging sovereign dollar bond spreads tightened 4 basis points to 368 bps over U.S. Treasuries 11EML .

The Hungarian forint erased early losses to gain 0.7 percent to 308.80 per euro EURHUF= , trading just off recent two-year lows.

The currency had been under pressure in recent weeks as expectations grew the central bank may cut interest rates further at next week's monetary policy meeting.

But interest rate markets believe the central bank may need to make a policy U-turn, and are pricing in rate rises of 85 bps over the next 9 months, according to Standard Bank.

For GRAPHIC on emerging market FX performance 2014, see http://link.reuters.com/jus35t

For GRAPHIC on MSCI emerging index performance 2014, see http://link.reuters.com/weh36s

For GRAPHIC on MSCI emerging Europe performance 2014, see http://link.reuters.com/jun28s

For GRAPHIC on MSCI frontier index performance 2014, see http://link.reuters.com/zyh97s

For CENTRAL EUROPE market report, see CEE/

For TURKISH market report, see .IS

For RUSSIAN market report, see RU/RUB )

(Additional reporting by Carolyn Cohn; Editing by John Stonestreet)

((natsuko.waki@thomsonreuters.com)(+44 207 542 6721)(Reuters Messaging: natsuko.waki.thomsonreuters.com@reuters.net)) 

 ((Emerging Markets Prices from Reuters              Equities                  Latest    Net Chg  % Chg  % Chg                                                                  on year              Morgan Stanley                 Emrg Mkt Indx   
  .MSCIEF
     943.59    +8.09   +0.86   -5.89               Czech Rep       
  .PX
        1011.79    +5.87   +0.58   +2.30               Poland          
  .WIG20
     2440.42   +29.06   +1.21   +1.64               Hungary         
  .BUX
      18235.16  +119.88   +0.66   -1.77               Romania         
  .BETI
      6361.51   +21.39   +0.34   -2.04               Greece          
  .ATG
       1262.31    +2.14   +0.17   +8.57               Russia          
  .IRTS
      1349.45   +13.43   +1.01  +16.06               South Africa    
  .JTOPI
    41493.08  +172.06   +0.42   +0.03                Turkey          
  .XU100
    64654.64  +604.48   +0.94   -4.64               China           
  .SSEC
      2103.67   +17.60   +0.84   -0.58               India           
  .BSESN
    20363.37   +29.10   +0.14   -3.81                            Currencies              Latest    Prev    Local    Local                                                  close   currency currency                                                        % change % change                                                                 in 2014              Czech Rep     
  EURCZK=
     27.52     27.53   +0.04    -0.68              Poland        
  EURPLN=
      4.18      4.18   +0.03    -0.66              Hungary       
  EURHUF=
    308.80    311.14   +0.76    -3.83              Romania       
  EURRON=
      4.47      4.47   -0.11    -0.26              Serbia        
  EURRSD=
    115.65    115.57   -0.07    -0.99              Russia        
  RUB=
        34.71     34.74   +0.07    -5.24              Kazakhstan    
  KZT=
       184.45    155.60  -15.64   -16.35              Ukraine       
  UAH=
         8.55      8.41   -1.64    -3.74              South Africa  
  ZAR=
        10.98     11.14   +1.39    -4.89              Kenya         
  KES=
        86.15     85.90   -0.29    +0.06              Israel        
  ILS=
         3.51      3.51   +0.00    -1.35              Turkey        
  TRY=
         2.20      2.21   +0.71    -2.42              China         
  CNY=
         6.06      6.06   -0.02    -0.11              India         
  INR=
        62.19     62.44   +0.41    -0.62              Brazil        
  BRL=
         2.40      2.41   +0.40    -1.53              Mexico        
  MXN=
        13.26     13.32   +0.51    -1.70                           Debt                 Index   Strip Spd  Chg   %Rtn   Index               Sov'gn Debt   
  11EML
   EMBIG   368         -4   0.05   629.27                            All data taken from Reuters at 1123 GMT.              Currency percent change calculated from the daily U.S.              close at 2130 GMT.                         ))

Keywords: MARKETS EMERGING