<p>SEOUL (Reuters) - Samsung Electronics Co Ltd missed already modest expectations for its quarterly earnings guidance on Friday, deepening worries that its smartphone business may have peaked, as growth in sales of its blockbuster Galaxy phones begins to wane and new rivals emerge to eat away at its market share.</p><p>The Galaxy S, powered by Google's free Android platform, propelled the South Korean firm into the top rank of smartphone makers in 2012, overtaking Apple Inc whose iPhone had set an industry standard five years earlier.</p><p>Now investors fear Samsung may also follow in the footsteps of Apple and other once-mighty players that are struggling with shrinking margins, in an industry where companies live and die by their ability to stay ahead of the innovation curve.</p><p>"Is Samsung's smartphone story now over? Not quite yet. It's growth is indeed slowing due largely to disappointing sales of the S4," said Jung Sang-jin, a fund manager at Dongbu Asset Management, which owns Samsung shares.</p><p><a href="http://www.reuters.com/article/2013/07/05/us-samsung-guidance-idUSBRE9630T920130705">Keep reading...</a></p><p>Read also:</p><p><a href="http://online.wsj.com/article/SB10001424127887324853704578586912248401322.html">Smartphone Success Is Samsung&#039;s Biggest Problem</a> (Wall Street Journal- India)</p><p><a href="http://mashable.com/2013/07/05/samsung-htc-earnings-analysis/">Samsung, HTC Earnings Disappoint: Is the Smartphone Market Saturated?</a> (Mashable)</p><p><a href="http://www.nypost.com/p/news/business/spillover_booby_traps_smartphone_J2rsIeCsn7uLttg7H4BzVJ">Spillover booby-traps smartphone market</a> (New York Post)</p><p>Explore: <a href="http://news.google.com/news/more?ncl=dUT3lFUn0AdT8iMzBkJu7StgDzxsM&ned=us">337 additional articles.</a></p>