STOCKHOLM (Reuters) - Swedish fashion group H&M (>> Hennes & Mauritz) will start holding capital market days, breaking with tradition and yielding to investor pressure although it also said it would stop posting monthly sales figures.

After decades of strong growth, sales growth at the world's second-biggest fashion retailer has slowed over the past couple of years amid tougher competition.

"A month is far too short a period over which to assess how sales are developing," H&M said in a statement. "Instead, sales development should be viewed over a longer period of time, such as over a season or a quarter."

H&M has published monthly sales data for more than a decade, albeit leaving out like-for-like figures since 2014.

A fund manager who declined to be identified said less information was never good.

"This shows how frustrated they are that the market has lost confidence in the company. The fundamental problem is not monthly data, it's the company's weak development," the fund manager said.

"Monthly data was not a problem when the company performed well. Why should it be now?"

H&M shares have been on a downward slope since 2015, underperforming the market and especially bigger rival Zara owner Inditex (>> Inditex SA), with the shares falling 18 percent in the past year alone. Analysts and investors have said the company is too tight-lipped on strategy and outlook.

In one concession, Chief Executive Karl-Johan Persson of the founding and main owner family last month for the first time took part in a quarterly public conference call about results.

H&M, which has never held a capital markets for investors since its listing in 1974, said it would begin to do so in order to provide "more in-depth information about the business".

Anders Oscarsson, head of ownership at pension fund AMF, one of H&M's biggest owners, welcomed the plans for capital market days. Dropping monthly sales publications was fine, he said, adding that the fund remained a long-term investor in H&M.

H&M, which does not publish earnings guidance, on Monday confirmed a preliminary June local-currency sales growth reading of 7 percent - in its last such monthly publication.

Shares were up 2.2 percent at 1115 GMT.

(Reporting by Anna Ringstrom, additional reporting by Olof Swahnberg, editing by Niklas Pollard and Susan Thomas)

By Anna Ringstrom

Stocks treated in this article : Hennes & Mauritz, Inditex SA