UPDATE 2-Experian fails to reassure as H1 sales rise 6 pct

(Recasts, writes through with shares, management comment, quotes)

By Clara Ferreira-Marques

LONDON, Oct 10 (Reuters) - Credit information provider Experian indicated a slowdown in second-quarter sales on Wednesday, helping send its shares down 8 percent amid concerns over the impact of U.S. mortgage market turmoil.

Experian Group Ltd (EXPN.L), best known for running consumer credit checks for banks, retailers and other companies, said sales rose 6 percent in the first half, down from 7 percent in the first three months of the year.

The latest number was broadly in line with market forecasts and Experian confirmed its full-year guidance of "mid to high" single-digit organic growth, a move welcomed by analysts who said it was showing increased resilience to a downturn.

But Experian shares plummeted 44 pence or 8.1 percent to 499p by 0912 GMT, a near two-month low, as units including LowerMyBills, which provides information on mortgages and loans, suffered the impact of a slowdown in U.S. lending.

The stock was the biggest loser in the FTSE 100 blue chip index .FTSE as analysts cited concerns over the outlook, particularly for LowerMyBills. Some 15 percent of Experian's profits last year were related to U.S. mortgage and property services.

Excluding LowerMyBills, organic sales growth in the six months to September would have been 2 percentage points higher.

Including the impact of its acquisitions in the six months, including Brazilian credit bureau Serasa, Experian said sales rose 14 percent at constant exchange rates.