* Insurer seeks 4 bln euros from asset disposals
* Targets 5 bln euros operating profit
* CEO Greco says won't cut dividend over three-year plan
* To expand P&C business, sees Solvency I above 160 pct
* Shares down 3.5 pct, underperform sector (adds fund manager comment, graphic, updates shares)
By Lisa Jucca and Myles Neligan
LONDON, Jan 14 (Reuters) - New Generali boss Mario Greco hopes to raise 4 billion euros ($5.3 billion) from selling non-strategic businesses, in a "revolution" aimed at turbocharging the Italian insurer's financial performance by 2015.
Europe's No.3 insurer has already put on the block Swiss private bank BSI and a U.S. life reinsurance unit, collectively valued at about 2.5 billion euros, but declined to say on Monday which other units might be sold.
Greco also said he was aiming to boost Generali's operating profit by a quarter by expanding the lucrative non-life insurance arm, investing more in fast-growing eastern Europe and Asia, and cutting 600 million euros ($800.7 million) of costs.
An outsider who took office on Aug. 1 backed by top shareholder Mediobanca, Greco also promised operating profit of more than 5 billion euros, up from an estimated 4 billion euros in 2012, though the period over which this would be delivered was specified only as "over the cycle".
Generali's reorganisation follows similar overhauls at rival European insurers Aviva, Axa and Old Mutual , who have all been forced to retrench to offset the impact of ultra-low interest rates and volatile financial markets following the 2008 banking crisis.
"We shall implement a revolution based on discipline, simplicity and focus," Greco said in London as he unveiled his road-map to boost profitability at Italy's main financial group.
"Today marks a significant milestone in reshaping Generali. The mandate from our shareholders is to improve returns and group profitability."
Underperformance at Generali, which suffered more than peers due to its large exposure to crisis-hit Italy, prompted frustrated investors to oust long-standing CEO Giovanni Perissinotto in a boardroom coup last year.
Under the new strategy, Generali aims to generate half its insurance operating profit from non-life insurance by 2015 from just about a third in the first nine months of 2012.
"This plan is about value, not volume," Greco said.
Generali also aims to lift its Solvency I ratio, the main measure of capital strength for European insurers, to 160 percent from an estimated 150-155 percent at end-2012, still below the average of 229 percent for its three biggest rivals.
The capital target takes account of a 2.5 billion euro deal last week to buy out Generali's GPH eastern European joint venture, a takeover that confirmed the Italian insurer's commitment to the region.
Greco promised to achieve the overhaul without cutting dividends, and said there would be no significant staff reductions in any of the regions where Generali operates.
He also said he would not scale back in mature markets such as Austria, Switzerland and the Netherlands, which some analysts see as underperforming, and had no acquisition plans in eastern Europe, where Generali gets about 6 percent of its sales.
Generali shares were down 3.4 percent at 1530 GMT, the second-steepest faller the Stoxx 600 European insurance index , which was down 0.6 percent.
The stock, also hit by news Czech investor Petr Kellner sold 1 million Generali shares last week, has risen 43 percent since Greco took over the top job in August, easily beating the sector's 26 percent gain.
"Expectations were high and after a good performance in recent weeks I think investors are taking the opportunity to take profits," said a Milan-based fund manager.
"The stock is trading at a premium to the sector and peers and does not warrant this in light of its balance sheet worries and challenges."
Generali's stock market gains reflect improved sentiment towards Italy that has boosted the value of Generali's Italian government bond portfolio of around 50 billion euros, a key weakness at the height of the euro zone sovereign debt crisis.
But it also reflects hopes for Greco's leadership, based on his track record at Italian insurer Ras, now part of Allianz , and Switzerland's Zurich Insurance.
The manager has already carried out an overhaul of Generali's opaque corporate governance and took on board foreign executives to truly mirror Generali's international presence.
Greco, who has already carried out a review of Generali's investment portfolio, said he has not yet received binding offers for BIS and the U.S. reinsurance activities.
"We are not forced sellers, so if we see offers that are not interesting, we will step back," he said. ($1 = 0.7493 euros) (Additional reporting by Gianluca Semeraro and Stephen Jewkes; Editing by Erica Billingham)