* Sterling extends gains, hits three-week high vs dollar * Pound further supported after Thursday's rally * Sterling set to end week higher vs major rivals
By Naomi Tajitsu
LONDON, Oct 16 (Reuters) - Sterling hit a three-week high against the dollar on Friday, extending the previous day's dramatic gains as traders who had bet on further falls in the pummelled pound rushed to cover their positions.
The pound was poised to end higher against major currencies in a week marked by whipsaw trade, which saw sterling claw back from a 6 1/2-month low versus the euro and its weakest in nearly five months against the dollar.
The UK currency extended gains a day after the market took talk of overseas interest in a UK firm and comments from a Bank of England policymaker that quantitative easing was working as an opportunity to cover short positions.
Traders continued to pick up the pound after it posted its biggest one-day gain against a basket of currencies in nearly a year on Thursday.
Short covering has breathed some life into the pound, which has come under heavy pressure in recent weeks, battered across the board on the view that UK interest rates will stay low and public finances will deteriorate further.
"It's possible the market is still piggy-backing on the M&A talk," said Geoffrey Yu, currency analyst at UBS in London.
Talk on Thursday that Qatar's sovereign wealth fund was planning a renewed offer for British supermarket chain J Sainsbury had helped spur sterling demand.
Also helping the pound were remarks by BoE board member Paul Fisher in a Financial Times interview on Thursday that the central bank's interest rate cuts and injections of money into the economy via asset purchases were working.
The central bank's ultra-easy monetary policy has contributed to pressure on the pound.
By 1026 GMT, sterling was up 0.2 percent at $1.6305, after climbing to $1.6401, its highest since late September.
"I favour buying (sterling/dollar) on dips at the moment," a London trader said. "I fancy another look at $1.6400."
The pound extended gains against the euro, which fell 0.4 percent to 91.45 pence. Earlier in the day, it hit a two-week low of 90.96 pence, falling from a 6 1/2-month high of 94.13 pence touched on Tuesday.
Against a currency basket sterling rose to 79.60, rising from a six-month low of 76.80 hit earlier in the week.
Sterling hit a three-week high around 149.35 yen.
VOLUMES, VOLATILITY RISE
Sterling's rollercoaster ride this week saw a spike up in the volume of sterling/dollar trades, which soared to around 17,500 on Thursday according to Reuters data, significantly higher than average levels around 10,000.
Volatility has also jumped, with one-month sterling/dollar options rising to around 12.75 percent on Friday, its highest in two months, and a sign that the pound may undergo further aggressive moves against the greenback. Volatility has risen roughly 1 percentage point from earlier in the week.
Given the higher volatility, analysts said they would focus on the pound's closing level on Friday to better determine whether the correction would continue. Phil Roberts, technical strategist at Barclays Capital, said a sterling/dollar close above $1.6125 would imply the downward correction from the 2009 high around $1.70 is over, while a euro/sterling close below 90.75 pence may confirm the tide has turned for the pound.
For a story on euro/sterling technical levels, click on
Sterling's rebound followed a hefty rise in speculator bets the currency would depreciate.
Data from the Commodity Futures Trading Commission on Friday showed currency speculators raised net pound short positions to 62,106 contracts in the latest week -- a record, analysts said -- from 47,826 contracts the week before.
For a graphic on the correlation between sterling positioning and its weakness against the euro, click on: http://graphics.thomsonreuters.com/109/UK_CFTGBE1009.gif
(Editing by Nigel Stephenson)