US president Donald Trump has blocked a planned takeover of chip maker Qualcomm by rival Broadcom on the grounds of national security.
His order cited "credible evidence" that the proposed $140bn (£100bn) deal "threatens to impair the national security of the US", reports the BBC.
There were reportedly concerns that the takeover could have led to China pulling ahead in the development of 5G wireless technology.
A takeover of Qualcomm by Broadcom would have created the world's third-largest maker of microchips, behind Intel and Samsung. The deal would have been the biggest technology sector takeover on record.
The race towards the latest 5G wireless technology is a vital part of the chip-making sector, with Qualcomm considered to be one of the leaders in this field, followed by Broadcom and China's telecoms giant Huawei.
Analysts say Qualcomm is regarded for its focus on research and development (R&D), especially in the field of 5G technology, reports the BBC. Broadcom is better known for selling assets and growing through acquisitions rather than R&D.
A deal between Qualcomm and Broadcom could have given Huawei the chance to take over the top spot eventually. This was deemed an issue for US politicians given their ongoing security concerns around Chinese telecom firms doing business with US carriers.
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