* FTSEurofirst 300 down 0.1 pct, slips from 2-month high
* Standard Life jumps on news of Canadian unit sale
* Big open interests for calls on euro zone bank index
By Blaise Robinson
PARIS, Sept 4 (Reuters) - European shares dipped in early trading on Thursday, taking a breather from the previous session's sharp gains, as investors waited to see whether the European Central Bank will unveil further immediate measures to avoid deflation.
Shares in Standard Life bucked the trend and surged 8.8 percent after it agreed to sell its Canadian operations for about $3.7 billion to Manulife Financial.
At 0748 GMT, the FTSEurofirst 300 index of top European shares was down 0.1 percent at 1,383.58 points, retreating from the two-month high hit in the previous session. The benchmark index has gained nearly 7 percent since early August.
"Stocks have been retracing the summer correction, but the rally now lacks momentum ahead of the ECB. A lot has been priced in already so risks are on the downside if Draghi disappoints," FXCM analyst Vincent Ganne said.
According to BNP Paribas equity derivative strategists, investor sentiment towards euro zone banks is bullish ahead of the ECB rate decision and press conference at 1230 GMT.
"Open interests for call options on the STOXX 600 euro zone bank index have surged over the last week. 1.5 billion euros notional was traded since the beginning of this week, compared to 500 million euros on puts," the strategists wrote in a note.
The ratio measuring the number of negative 'put' options versus bullish 'call' options on the euro zone's blue-chip Euro STOXX 50 index - the most liquid European market for options traders - has dropped sharply in the past three weeks, hitting 0.93 earlier this week, down from 2.45 in early August.
The euro zone banking index - which has surged 12 percent since early August but remains 9 percent below the year's highs hit in April - was down 0.1 percent on Thursday.
Societe Generale was up 0.4 percent and BBVA down 0.2 percent.
Shares in Commerzbank AG rose 0.5 percent. Sources told Reuters the German lender is close to reaching a deal with U.S. authorities over its dealings with Iran and other countries under U.S. sanctions.
Europe bourses in 2014: link.reuters.com/pap87v
Asset performance in 2014: link.reuters.com/gap87v
Today's European research round-up (Editing by Sonya Hepinstall)