STX Group scrapped plans to buy a stake in Hynix Semiconductor Inc., leaving mobile-phone operator SK Telecom Co. as the only suitor left to bid for 20 percent of the world’s second-largest computer-memory chipmaker.The South Korean shipbuilding and shipping group dropped its interest because of concerns over the level of investments needed to keep the chipmaker competitive and global economic uncertainties, STX Corp., which was planning to lead the group’s bid, said in a statement today in Seoul. The 146.1 million shares up for sale are valued at 3.1 trillion won ($2.7 billion) based on Hynix's latest stock price.STX Chairman Kang Duk Soo’s withdrawal removes the only competition SK Chairman Chey Tae Won faced in making a bid in defiance of analysts at brokerages including Morgan Stanley and Daiwa Securities Group Inc., who oppose the idea of a phone operator buying control of a chipmaker. Hynix’s main shareholders, who have failed to sell their stake three times since 2009, said they will discuss how to proceed with the sale.“SK Telecom and shareholders are now going to have to have one-on-one talks,” Shin Hyun Joon, a Seoul-based analyst at Dongbu Securities Co. said by telephone. Because of reduced competition, “you can’t rule out the possibility that the sale could fall through,” Shin said.Hynix fell 4.1 percent to close at 21,000 won in Seoul trading. STX Corp., which was teaming up with Aabar -- a state- run United Arab Emirates investment company -- for its bid, rose 3.8 percent. SK Telecom declined 3.5 percent.SK Telecom hopes Hynix shareholders will proceed with the sale, Lauren Kim, a Seoul-based spokeswoman for the carrier said by telephone. The company will review the results of its due diligence, the outlook of the chip industry and details of sale conditions to make a “reasonable” decision,’’ she said.Hynix’s main shareholders will discuss whether they will proceed with their current plan, said Lee Sun Hwan, Seoul-based spokesman for Korea Exchange Bank. (004940) Park Seong Ae, a Seoul-based spokeswoman for Hynix, declined to comment on STX’s decision.STX said delays in reaching an agreement with its Middle Eastern bidding partner was also a factor that contributed to its decision.Hynix shareholders, led by Korea Exchange Bank, said this month they plan to sell a 20 percent stake that includes 101.85 million new shares and 44.25 million existing ones held by shareholders.The shareholders, a group of financial institutes that spent $4.6 billion to bail out the chipmaker in the past decade, had planned to receive bids for Hynix by Oct. 24 and select a preferred bidder by the end of October.Hyosung Corp., the sole bidder in a sale attempt two years ago, walked away from negotiations in November that year, saying speculation that it received political favors to pursue the takeover made it difficult to negotiate a fair acquisition.