* Majority of board had called for CEO Tanoh to step down
* Row a test case for African financial regulators
* Tanoh defenders say he sought to expose prior abuses (Updates with bank statement, writes through)
By Matthew Mpoke Bigg
ACCRA, March 11 (Reuters) - The board of Ecobank removed its chief executive, Thierry Tanoh, on Tuesday following months of turmoil at one of the biggest financial institutions in sub-Saharan Africa.
The crisis over corporate governance and leadership that led to Tanoh's departure is seen as a test case for regulators and has put a spotlight on the integrity of financial institutions on a continent where economies are expanding rapidly.
Ecobank named Deputy CEO Albert Essien as its new chief executive. It also announced the reinstatement of finance director Laurence do Rego, which was a demand by Nigeria's securities regulator, which is investigating alleged breaches of corporate governance.
"Ecobank Transnational Incorporated today announces the departure of Group CEO Mr Thierry Tanoh with effect from 12 March 2014. Effective the same date he will no longer be a director of ETI," the bank's holding company said in a statement.
Tanoh could not immediately be reached for comment.
Tanoh's supporters have said he was under pressure because of his drive to expose and correct abuses of corporate governance that pre-dated his tenure, which attracted powerful enemies nervous of what he might uncover.
Essien, who is from Ghana, has been at Ecobank for more than 20 years and rose to deputy group CEO two years ago.
The 12-member board made its decision at a meeting in Yaounde, the capital of Cameroon, a senior bank official said. Tanoh did not attend.
The Ivorian took the reins as CEO in January 2013, having previously served as a vice president at the International Finance Corporation, the investment arm of the World Bank.
Ecobank is based in Togo and has a presence in 35 African countries. There are few other pan-African banks, and the continent's biggest financial institutions are based in South Africa.
Under Tanoh, profits grew 56 percent in the first nine months of last year, and his defenders said those results reflected his leadership qualities.
But his tenure was also marked by a row over his bonus and by an investigation launched last August by Nigeria's Securities and Exchange Commission (SEC) after do Rego told the regulator that Tanoh had pressured her to misstate 2012 financial results.
Ecobank denied that allegation and said do Rego had previously been suspended in a dispute over her qualifications.
The SEC in January criticised what it said was an absence of clear vision and strategy at the bank, inadequate transparency in recruiting and conflicts of interest.
It also demanded that do Rego be reinstated as a whistleblower, something the bank said would be against Togolese law.
Last week, shareholders at an extraordinary general meeting voted to implement reforms designed in part to answer the regulator's criticism. In an apparent snub to Tanoh, they also told the board to reinstate do Rego.
A senior Ecobank official played down the impact of the crisis on the bank.
"It's obviously caused people to be a bit concerned, but if you look at the share price it is slightly down this year, but it is still much higher than at the end of 2012," the official said.
BOARD ROOM BATTLE
Tanoh's position as CEO was undermined by a series of defections from the board at a bank that had attracted little adverse publicity under the long tenure of its previous CEO, Arnold Ekpe.
"This (Tanoh's departure) was just a matter of time. I expect a positive response in terms of the market's view of Ecobank's corporate governance," an institutional investor said, declining to be named.
Four executives on Tanoh's top five-person committee wrote on Feb. 13 to interim Chairman Andre Siaka to say Tanoh should resign to solve a crisis of leadership.
That email was sent by Essien, who was executive director of corporate and investment banking in addition to his duties as deputy CEO.
On March 1, non-executive board member Daniel Matjila denounced Tanoh in a letter to Siaka and the board, calling for his contract to be terminated immediately. Matjila represents South Africa's Public Investment Corporation, the bank's largest shareholder with 18.35 percent.
His letter had the support of two other board members, which had amounted to a total of seven who came out publicly to oppose Tanoh before Tuesday's meeting. (Additional reporting by Chijioke Ohuocha in Lagos and Tiisetso Motsoeneng in Johannesburg; Editing by Joe Bavier and Jane Baird)