By Andrew Torchia

DUBAI, July 25 (Reuters) - Poor corporate earnings, due in part to Saudi Arabia's austerity policies and sluggish economic growth, weighed on the Saudi stock market on Tuesday as most regional bourses were virtually flat.

The Saudi stock index .TASI fell 0.3 percent in thin trade. National Shipping Co (Bahri) 4030.SE sank 5.6 percent after reporting that quarterly net profit plunged to 153.9 million riyals ($41.0 million) from 487.1 million riyals a year earlier, as revenues also tumbled. It cited lower shipping spot market rates and higher bunker costs.

Al Yamamah Steel 1304.SE lost 4.9 percent after reporting a quarterly profit of 17.2 million riyals, down from 67.9 million riyals, as sales fell steeply.

Saudi Arabia Fertilizers Co (SAFCO) 2020.SE dropped 2.8 percent after quarterly profit shrank to 204.3 million riyals from 302.3 million riyals and sales declined. And home appliance distributor Shaker 1214.SE tumbled 6.4 percent after swinging to a quarterly net loss as sales dropped sharply.

However, National Gas and Industrialization 2080.SE edged up 0.3 percent after quarterly profit climbed to 37.8 million riyals from 23.0 million riyals. Dallah Healthcare 4004.SE rose 0.9 percent after quarterly profit rose to 70 million riyals from 54.1 million riyals.

In Dubai, the index .DFMGI edged down 0.1 percent as blue chip Emaar Properties EMAR.DU slipped 0.4 percent.

Telecommunications firm du DU.DU rose only 0.5 percent after reporting a quarterly net profit of 446.6 million dirhams ($122 million), almost unchanged from a year earlier but well above forecasts of 373.2 million dirhams by SICO Bahrain and 409.3 million dirhams by EFG Hermes.

The results ended a major earnings slump; du had reported declining year-on-year profits in the preceding 10 quarters. Revenues rose from a year ago and the first-half dividend stayed the same.

Unusually, the two most heavily traded stocks were Islamic insurers, with Islamic Arab Insurance SALAMA.DU gaining 3.5 percent and Dubai Islamic Insurance AMAN.DU soaring 13.7 percent.

Qatar's index .QSI edged up 0.2 percent as Qatar Gas Transport (Nakilat) QGTS.QA , the most active stock, fell 1.8 percent after saying first-half profit dropped to 408.3 million riyals ($112 million) from 500.3 million riyals, although revenue declined less sharply.

Al Meera Consumer Goods MERS.QA , which has not yet released quarterly earnings, jumped 5.8 percent in its heaviest trading volume since November 2014.



HIGHLIGHTS



SAUDI ARABIA



* The index .TASI fell 0.3 percent to 7,228 points.



DUBAI



* The index .DFMGI edged down 0.1 percent to 3,595 points.



ABU DHABI



* The index .ADI edged up 0.04 percent to 4,542 points.



QATAR



* The index .QSI edged up 0.2 percent to 9,595 points.



EGYPT



* The index .EGX30 edged down 0.1 percent to 13,740 points.



KUWAIT



* The index .KWSE rose 0.2 percent to 6,833 points.

BAHRAIN



* The index .BAX climbed 0.5 percent to 1,335 points.



OMAN



* The index .MSI edged up 0.1 percent to 4,998 points.

(Reporting by Andrew Torchia; Editing by Susan Fenton) ((andrew.torchia@thomsonreuters.com; +9715 6681 7277; Reuters Messaging: andrew.torchia.thomsonreuters.com@reuters.net))