Bulgarian tycoon Tsvetelina Borislavova, more publicly known as the woman with whom Prime Minister Boyko Borisov formerly lived out of wedlock, has returned in the banking sector with a sizable purchase.

Through her company Clever Synergies Investment Fund (CSIF), Borislavova bought Monday 49.99% of the Bulgarian-American Credit Bank, the CSIF announced.

The contract for the sale of 49.99% of the Bulgarian-American Credit Bank was signed Monday between the previous owner of the share, the Allied Irish Bank (AIB).

The sale is yet to be approved by the Bulgarian National Bank and the Competition Protection Commission.

The Bulgarian-American Credit Bank (BACB) is a public bank listed on the Bulgarian Stock Exchange. As of December 31, 2010, its assets amounted to EUR 375.9 M.

CSIF is a private investment company founded in 2005; its shareholders are Tsvetelina Borislavova and her foundation Credo Bonum.

In December 2010, Tsvetelina Borislavova, believed to be one of the richest Bulgarians, and described in various rankings as one of the most powerful Bulgarian women, formally left the banking sector as the Belgian banking group KBC acquired full control over its subsidiary in Bulgaria CIBank.

Back then the prime minister's long-time live-in girlfriend Tsvetelina Borislavova sold her last 16% stake. The price of the deal exceeds BGN 141 M or BGN 110.49 per share.

KBC agreed to buy 75% in the bank, initially called EIBank, for EUR 295 M in September 2007 and secured the approval of both the central bank and competition authorities at the end of the year.

The group bought half the stake of board chairwoman Tsvetelina Borislavova and the full stake held by Novator investment fund, which manages the Bulgarian assets of Icelandic mogul Thor Bjorgolfsson.

That was the second major acquisition by the Belgian group in Bulgaria, having agreed earlier that year to buy 70% in insurer DZI, later boosting its stake to 85%.

Initially, Borislavova kept 22.3% of her shares and became "KBC's partner", keeping her position as chair of the supervisory board.

Subsequently KBC launched a buyout offer to the minority shareholders in the bank and gradually increased its capital.

Bulgaria's Economic and Investment Bank (EIBank) changed its name to CIBank in October 2008 without giving reasons for its decision.