In its first statistical report since merging with Archipelago last month, the

NYSE Group

(NYX)

said that its share of trading volume in NYSE-listed stocks fell in March from the previous month and the same period last year.

The NYSE's market share fell to 74.6% from 76.2% last month and 80.5% in March of last year. The reported figures showed the combined NYSE and Archipelago trading data and previous months were adjusted to reflect combined data as well.

As the NYSE rolls out its "hybrid" market platform, which includes floor and electronic trading through the newly acquired Archipelago exchange, the distinction between shares listed on either the Big Board or Nasdaq blurs. Both exchanges have fought to poach market share from each other through their respective electronic platforms. For this reason, the industry has become doggedly competitive.

The decline in volume on the NYSE followed a frenzy of trading in one of the NYSE's most active stocks,

Lucent

(LU)

-- on the

Nasdaq

I:IXIC

. Last week, the Nasdaq reported a single-day trading record in NYSE-listed shares on March 24. It attributed the record to increased volume in Lucent shares.

NYSE increased its share of Nasdaq-listed issues during the month, boosting the share to 19.2% in March from 18.5% in February. That's also up from a 17.5% share in the same period last year.