UPDATE 1-Malaysia's CIMB logs first quarterly profit drop since 2015

* Q1 profit fell without one-off gain logged a year ago

* Lower profit in consumer and corporate banking, loss in investment banking

* Rest of 2019 challenging amid trade tensions, other macro-economic headwinds - CEO (Updates with earnings details)

KUALA LUMPUR, May 29 (Reuters) - CIMB Group Holdings Bhd on Wednesday logged its first quarterly profit drop since 2015, with year-ago results being inflated by a one-off gain, while the Malaysian lender also flagged a challenging year ahead.

The lender also reported a profit drop in its consumer, corporate segments and a loss in investment banking unit, a bourse statement showed.

CIMB, Malaysia's second-largest lender by asset, has been posting consecutive quarterly earnings growth since the end of 2015.

"We expect the rest of 2019 to remain challenging, amid fresh trade tensions and other macro-economic headwinds, coupled with tougher operating conditions in our major markets," CEO Zafrul Aziz said in a statement.

Malaysia's economy grew faster than expected in the first quarter at 4.5% supported by a recovery in the agriculture sector, but weakening global demand and the U.S.-China trade war are seen increasing risks for the country.

A year ago, CIMB charted its highest quarterly profit in five years lifted by lower costs and provisions as well as a one-off gain.

The bank's profit for the three months ended March was 1.19 billion ringgit ($283.74 million), compared with 1.31 billion ringgit in the same period last year.

The net profit, however, was higher than the 777.9 million ringgit average estimate from two analysts polled by Refinitiv.

Revenue came in at 4.17 billion ringgit, a 3% drop from the previous year.

Meanwhile, CIMB's total gross loans grew 7.6% versus a year ago, while deposits rose 5.6%.

Net interest margin (NIM) - a measure of bank profitability - came in at 2.48% in the first quarter, CIMB said.

The lender's net interest income grew 1.7% to 2.46 billion ringgit.

Bigger rival Maybank is expected to report its first-quarter results on Thursday.

($1 = 4.1940 ringgit) (Reporting by Liz Lee, Editing by Sherry Jacob-Phillips)