* H1 underlying pretax profit down 40 pct
* Revenues down 20 pct; interim dividend 7.5 p/share
* Shares down 4.8 pct, leading FTSE mid-cap fallers (Adds detail from statement, share price reaction)
By Simon Jessop
LONDON, May 3 (Reuters) - British fund firm Aberdeen AssetManagement posted a 40 percent fall in first-halfunderlying pretax profit, hit by a slump in emerging marketsthat it said would likely lead to further asset outflows.
A bellwether for investor sentiment to the highly volatiledeveloping economies of Asia, Africa and Latin America, the firmhas seen billions of pounds in assets flee its funds amidconcerns around global growth.
The firm reported underlying pretax profits for the sixmonths to end-March of 162.9 million pounds ($239.84 million) onrevenue down 20 percent to 483.6 million pounds.
The heavy outflows pushed assets under management at the endof March down to 292.8 billion pounds from 330.6 billion.
"These results reflect challenging conditions Aberdeen hasfaced during past three years, in particular weakness inemerging markets," Martin Gilbert, Chief Executive of AberdeenAsset Management, said in a statement.
While the impact of persistent asset outflows had beentempered by an emerging market rally in recent weeks andcurrency gains, the company said it remained vulnerable tofurther outflows over the next few quarters.
The scale of the fall combined with a still-weak outlooksent Aberdeen's shares lower at the open, and by 0707 GMT theywere trading down 4.8 percent at 285.3 pence a share onBritain's mid-cap index.
Aberdeen said it would pay an interim dividend of 7.5 pencea share and planned to deliver 70 million pounds of annualisedcost efficiencies during 2017.
($1 = 0.6792 pounds) (Reporting by Simon Jessop; editing by Sinead Cruise and JasonNeely)
