United States-based Bramson, Electra's largest shareholder with a nearly 20 percent stake via his investment vehicle Sherborne, had requested a place on the board with a pledge to shake up the company and more than double its market value.

Bramson's approach was rejected by Electra shareholders last month, which also served to ease the concerns of companies within a portfolio that the fund said had performed strongly, helping its diluted net asset value (NAV) per share to 31.74 pounds in the year to Sept. 30.

Electra, one of the City of London's oldest private equity funds, also said on Thursday that it had invested 410 million pounds ($648 million) over the year, boosting its portfolio to 1.27 billion pounds with a return per share of 419 pence.

The diluted NAV, which takes into consideration outstanding convertible bonds, was equivalent to a 10-year annualised return of 14 percent, at the upper end of its long-term target of 10-15 percent a year.

After last month's shareholder vote, Electra said it would conduct a review of the fee arrangements, capital structure and distribution policy that had been criticised by Bramson.

Chairman Roger Yates told Reuters that the review is still a work in progress and it would be another few weeks before the company is in a position to announce its findings, adding that there had been no contact with Bramson.

Electra also said that it is in exclusive or second-round talks over potential new investments in assets totalling 300 million pounds, adding that it sees cash-generative businesses as underpriced by the market in favour of growth stories.

The fund said that its acquisitions over the year were made at an average of 7.5 times core earnings (EBITDA), against a market average of 10.6 for deals over 10 million pounds.

Portfolio returns were driven in particular by newer investments, including AXIO Data Group, Park Resorts and South Lakeland Parks, all made within the past three years.

Electra's shares were up 4.1 percent by 0941 GMT, one of the biggest risers on the FTSE 250 index.

(Reporting by Freya Berry; Editing by David Goodman)