DUBAI- Qatar National Bank, the Gulf's biggest lender, issued 1.1 billion yuan ($167.97 million) in three-year bonds on Thursday, a document seen by Reuters showed.

It was the second international debt issue by a Qatari bank in as many days as Commercial Bank sold 150 million Swiss francs ($161.55 million) in three-year bonds on Tuesday, according to two sources.

Both banks tap the international debt markets regularly and have previously raised debt in currencies other than the U.S. dollar to diversify their investor base.

While they have both issued dollar-denominated bonds this year, Qatar National Bank (QNB) also raised 1.5 billion yuan in five-year bonds in January and Commercial Bank (CBQ) raised 185 million Swiss francs in four-year bonds last November, according to Refinitiv data.

Standard Chartered  was the sole lead manager on Thursday's issue by QNB, according to a note issued to investors and seen by Reuters.

The bonds were issued at a yield of 3.5%; while CBQ's issue on Tuesday had a coupon rate of 0.195%, according to the sources.

Deutsche Bank and Credit Suisse arranged CBQ's bond issue, one of the sources said and Refinitiv's IFR, a fixed income news service, reported.

Qatar National Bank, Commercial Bank and Credit Suisse did not immediately respond to requests for comment. Standard Chartered and Deutsche Bank declined to comment.

($1 = 6.5488 Chinese yuan renminbi)

($1 = 0.9285 Swiss francs)

(Reporting by Yousef Saba; Editing by Susan Fenton) ((Yousef.Saba@thomsonreuters.com; +971562166204; https://twitter.com/YousefSaba))