Mahmoud, who argues Islamic banking is only part of a larger move towards ethical banking in the post-crisis world, took over the helm of ADIB in 2008 after a 22-year stint at Citigroup. He says the value proposition of Islamic banks already extends to non-Muslim clients.
Earlier in April, ADIB acquired the retail operations of Barclays in the United Arab Emirates for a price tag of $177 million, giving it access to expatriate customers. The purchase will see 110,000 accounts transferred to Sharia-compliant accounts.
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Islamic finance asserts that currency has no intrinsic value and must be directly attributed to an underlying asset. It also prohibits the collection and payment of interest, speculative or derivative instruments, as well as investments in breach of its code of ethics.
"It's all about ethics and I think that's where the future is going. Can we finance hotels? Yes. Do we finance hotels that sell alcohol and gambling? The answer is no" Mahmoud said.
The global Islamic finance industry is expected to double to $2.6 trillion by 2017, according to a recent report by financial services firm PwC.
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"We believe it's only a matter of time before it achieves critical mass, as the pool of assets broadens and deepens, and enhances liquidity," Standard & Poor's said in its 2014 Global Islamic Finance Outlook .
It's a niche other banks, including Deutsche Bank, Citi, UBS and Barclays, are tapping into, offering their own Sharia-compliant banking products.
Sovereigns are also following. The Hong Kong government plans to issue up to one billion U.S. dollars' worth of sukuk, or Islamic bonds, in 2014. In October, British Prime Minister David Cameron revealed plans to issue $335 million worth of sukuk.
There is a substantial amount of research emerging about whether Islamic finance offers systemic benefits to the global economy.
"We have been through the biggest stress test, at the end of 2008. I think we all saw who fell down and who didn't. We do not speculate in derivatives," Mahmoud said.
"Islamic banks by mandate, by doctrine, are tied to the real economy, to real assets."
Sharia-compliance doesn't necessarily make a bank trouble-free, however. In a report on ADIB, Fitch Ratings cited "underlying weak asset quality, exposure to problem financing, sizable loan concentrations and renegotiated loan book, and consequent vulnerability to event risk and potentially high losses."
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But the report also noted the "ability and willingness of the UAE federal authorities to support ADIB" if needed due to the lender's "systemic importance."
ADIB has a footing in seven countries including the UAE, and is eyeing Saudi Arabia, Algeria, Turkey, Iraq, Algeria and Iran as strong contenders for future expansion.
"What we look for is an ecosystem that is good for our business model so a large population base with a large economic base is what retail banks look for. We are predominantly a retail bank," Mahmoud explained.
Last week, ADIB posted a 20.4 percent increase in first-quarter net profit, driven by higher lending. Its stock is up over 40 percent so far this year, outperforming the benchmark Abu Dhabi Securities Exchange (ADX).