* Fund CEO resigns days after cabinet reshuffle
* PIC biggest asset manager in Africa
* Masilela had pushed developmental agenda (Recasts, adds details)
By David Dolan and Tiisetso Motsoeneng
JOHANNESBURG, May 30 (Reuters) - The chief executive of South Africa's government pension fund has resigned, the fund said on Friday, following three years at the helm of the continent's largest and most influential asset manager.
Elias Masilela's unexpected resignation from the Public Investment Corporation (PIC) comes just days after President Jacob Zuma reshuffled his cabinet, promoting former deputy finance minister, 55-year-old Nhlanhla Nene, to finance minister.
It was not immediately clear whether Masilela had chosen to go or had been prompted to resign by changes in the finance ministry, which oversees the fund. In his capacity as deputy finance minister, Nene was also the chairman of the PIC.
No one was available to comment at the PIC or the finance ministry.
Masilela will formally resign on June 30, but will take his outstanding leave with immediate effect, the PIC said in a statement. Chief Financial Officer Matshepo More has been appointed acting CEO.
The PIC, which has major stakes in some of South Africa's largest companies as well as other investments in sub-Saharan Africa, manages pensions on behalf of government employees.
Under Masilela, the fund's assets under management grew to 1.6 trillion rand ($154 billion) and it increased exposure to African countries outside its home market and to alternative investments such as private equity.
The fund is well known in South Africa for its often activist stance - it has castigated companies over executive pay and has been a vocal opponent of at least one recent deal.
Last year it opposed a $1.2 billion bid for drugmaker Adcock Ingram from Chilean suitor CFR Pharmaceuticals . The PIC, at the time Adcock's top shareholder, said it did not want to swap its Adcock stock for that of CFR.
Its opposition helped pave the way for a successful bid from South African firm Bidvest, in which the PIC is also a shareholder.
Masilela has also tried to use the PIC to pursue a development agenda in Africa, even as some critics said the fund should focus on the considerable development needs at home.
Masilela had argued that growth in Africa would ultimately help South Africa's economy, reducing unemployment.
"Do South Africans fully understand that? I'm not convinced that they do," he told Reuters in an interview in March. (Writing by David Dolan; Editing by Stella Mapenzauswa and Stephen Addison)