There had been uncertainty over GFH Capital's intentions for the Elland Road outfit, with some suggestions that they were looking to offload completely.
However, it appears that is not the case.
Instead, GFH is recruiting "strategic investors" to strengthen the club's financial position, which it believes is necessary if Leeds are to regain their former status as a Premier League heavyweight.
IIB's chief executive, Aabed Al-Zeera, will join the Board of Leeds City Holdings Limited.
David Haigh, deputy chief executive of GFH Capital, said: "The introduction of IIB is in keeping with what have always been GFH Capital's aims for the successful, sustainable and long term ownership of Leeds United FC.
"We believe that a consortium of like-minded investors provides the best ownership model for a club which belongs among the elite of English football clubs and global sporting brands.
"It is our aim to provide the finance and the stability to enable the club to complete that journey as soon as possible."
GFH expects other investors to join, providing Leeds with "sound long-term finance", said the club.
International Investment Bank B.S.C was launched as an Islamic Investment Bank in October 2003.
On its website, IIB states the "core business activities of the Bank include investing on its own account and investment, underwriting and placement in real estate and private equity in conformity with Islamic Shari'ah".
Al-Zeera said: "We are delighted to become investors in Leeds United and would like to thank GFH Capital for facilitating this for us."
Whilst fans may wonder at the wisdom of investment from yet another Bahrain-based organisation, GFH insists it is the only way Leeds can recover their former status, having been relegated from the Premier League in 2004.
Since then, the West Yorkshire outfit have been mired in financial woe, even dropping into League One in 2007.
Although they were able to clamber out of English football's third tier, it has proved impossible to reach the Premier League.
GFH Capital took control of the club from Ken Bates last December and claims to have already invested £10million in the Elland Road outfit, beyond the sum it took to acquire ordinary shares in the first place.
Amongst the benefits of GFH's ownership, fans have already seen a reduction in match ticket prices, the introduction of half season tickets and a reduction cost of season tickets for 2013-14.