DUBAI, Oct 18 (Reuters) - Qatar Islamic Bank QISB.QA (QIB), the Gulf state's largest sharia-compliant lender by assets, met the average forecast of analysts as it reported a 6.8 percent rise in third-quarter net profit on Tuesday, according to Reuters calculations.

It made a net profit of 550.0 million riyals ($151.1 million) during the three months to Sept. 30, compared with 515.2 million riyals in the same period a year earlier, Reuters calculated from financial statements in the absence of a quarterly earnings breakdown.

Four analysts polled by Reuters had forecast on average the bank to make a quarterly net profit of 550.7 million riyals.

QIB posted net profit of 1.61 billion riyals in the first nine months of the year, up 14 percent on a year earlier, according to a bourse statement.

Total lending jumped 17 percent year on year to 97 billion riyals, and deposits gained 11 percent over the same time period to 96 billion riyals.

The bank in September raised 2 billion riyals with an Additional Tier 1 perpetual sukuk issue, aimed at enhancing the bank's capital adequacy ratios and supporting its business growth.

($1 = 3.6412 Qatar riyals)

(Reporting By Tom Finn; Writing by Tom Arnold; Editing by David French) ((Tom.Arnold@thomsonreuters.com; +97144536265; Reuters Messaging: tom.arnold.thomsonreuters.com@reuters.net))