By Marie Mannes and Helen Reid

STOCKHOLM (Reuters) -H&M scrapped its margin target for 2024 as higher discounting, costs and fierce competition hurt operating profit in the third quarter, denting shares in the world's second-biggest listed fashion retailer.

The Swedish retailer had cautioned in June that factors such as material costs made the 2024 target harder to reach, but ditching the goal with no new margin guidance for next year increases the pressure on CEO Daniel Erver to accelerate the turnaround.

H&M said a strong Swedish crown and costs related to shutting down its online fashion outlet Afound hurt profit, and that the cost of markdowns had increased over the quarter.

It has also boosted marketing spending, hiring pop star Charli XCX, for example, for a London Fashion Week party launching its autumn/winter collection, as part of Erver's strategy to elevate the brand.

H&M's operating margin for the first three quarters was 7.4%, with a third-quarter margin of 5.9%. The last year H&M produced a double-digit operating margin was 2017, and Erver said 10% remained a long-term goal.

"The growth rates were widely expected so shouldn't be a huge surprise but the margin weakness will continue to disappoint," said Bernstein analyst William Woods.

Shares in H&M dropped 8% at the open before paring losses to trade down 3.2% by 0940 GMT.

It has struggled to compete against its bigger Spanish rival Zara, owned by Inditex, and cut-price online fast-fashion retailer Shein, amid high inflation and weak consumer demand.

H&M said it would buy back shares worth 1 billion Swedish crowns ($98 million), from Sept. 26 to Nov. 26. The shares have lagged Inditex's over the past years and are down 5% so far this year.

MARKETING BLITZ

Erver defended his plan, saying H&M was "raising the bar" and strengthening its brand by investing in marketing, products, and the shopping experience.

"It is an investment to create excitement around the H&M brand," he told Reuters in an interview. "We will continue this effort throughout the fourth quarter and then we will evaluate and decide how we play it into 2025."

H&M said its autumn collection was very well received and that it expects September sales to rise by 11% in local currencies compared with the same period last year.

The retailer has been on a marketing blitz for the collection, hosting 12 events in eight cities overall, including the London launch, to market the clothes.

H&M, which does not publish granular figures on marketing, said spending in the fourth quarter would be "a little higher" than the third quarter.