DUBAI - Abu Dhabi Commercial Bank (ADCB) and Abu Dhabi Islamic Bank (ADIB) raised $1.25 billion combined from the sale of conventional and Islamic bonds on Tuesday, seizing a window of opportunity to raise debt amid a lull in regional issues.

ADCB launched $500 million five-year senior unsecured bonds at 120 basis points (bps) over U.S. Treasuries (UST), 10 bps tighter than guidance earlier in the day, a bank document showed.

Barclays, Deutsche Bank, Emirates NBD Capital, JPMorgan, Mizuho and ADCB itself acted as joint bookrunners on the deal.

ADIB tapped markets for $750 million perpetual Islamic bonds with a yield of 7.25%, a separate bank document showed. The Additional Tier 1 (AT1) sukuk are non-callable for 5-1/2 years.

AT1 bonds, the riskiest debt instruments banks can issue, are designed to be perpetual in nature, but lenders can redeem or "call" them after a specified period.

The final yield tightened significantly from earlier guidance of 7.875% after order books topped $7 billion, signaling strong demand from investors.

HSBC and Standard Chartered are joint global coordinators and structurers for the issue, joined by ADIB, Citi, Emirates NBD Capital, First Abu Dhabi Bank, and JPMorgan as joint bookrunners and lead managers.

Both debt sales will price on Tuesday.

They follow a $300 million sukuk sale on Monday by Dubai real estate developer Sobha Realty, the first public bond sale out of the Gulf since Commercial Bank of Dubai sold $500 million in green bonds just over a month ago.

Debt issues in the region have lulled amid uncertainty over interest rates.

(Reporting by Yousef Saba; Writing by Rachna Uppal; editing by Jason Neely and Emma Rumney)