April 17 (Reuters) - Netflix ( NFLX ) shares fell nearly 10% in premarket trading on Friday after chairman and co-founder Reed Hastings said he was leaving the company at a pivotal moment, as the streaming pioneer hunts for new growth avenues following a failed deal with Warner Bros Discovery ( WBD ).

In a letter to investors, Netflix ( NFLX ) on Thursday said Hastings will not stand for re-election at its annual meeting in June and plans to focus on philanthropy and other pursuits.

"This was unexpected news, and Hastings is seen as the DNA of the company," said Kathleen Brooks, research director at XTB.

Hastings, who co-founded the firm 29 years ago, has been the backbone of Netflix's ( NFLX ) roller-coaster transformation from a DVDs-by-mail business to a global streaming giant and steered the company through strategic hiccups and difficult periods such as the pandemic.

The co-founder also led the failed high-stakes bidding war earlier this year to acquire Warner Bros Discovery ( WBD ), which would have handed Netflix ( NFLX ) a clutch of prized franchises including "Game of Thrones" and "Friends".

"Hastings' departure from Netflix ( NFLX ) has jolted investors at an interesting time for the company," Brooks said.

The move comes at a time when the streaming giant faces slowing revenue due to stiff competition that has prompted the "Stranger Things" maker to venture into new growth avenues including ad-supported content, live sports and gaming.

"While some of that valuation decline will also be investor disappointment at Hastings leaving the business, it's fair to say that Netflix ( NFLX ) is not usually in the habit of coming up short with earnings strength," said Dan Coatsworth, head of markets at AJ Bell.

Netflix ( NFLX ) shares have lost more than 18% since early December, when it first submitted a bid for Warner Bros. On February 26, the firm said it was walking away from the deal and since then, the stock has gained 21%.

The company on Thursday surpassed first-quarter revenue and profit estimates, forecasting earnings per share for the current quarter below analysts' expectations and quarterly revenue growth that will the slowest in a year, according to LSEG data.

Investors are now squarely focused on returns from the streaming giant's aggressive push to broaden its live offerings as well as revenue growth from price hikes.