Abstract: The killer acquisition of start-ups by large digital platform enterprises for the purpose of eliminating potential competitive threats and consolidating the existing monopoly position is a major challenge to the regulation ofoperators' concentration in various anti-monopoly jurisdictions.Due to the short period of establishment and small scale of start-ups,such mergers and acquisitions usually fail to meet the pre-declaration standards and cannot enter the competition review process,and even if they have entered the subsequent competition review,it is difficult to legally stop or get relief due to the difficulty of assessing and proving competition damage.In view of this,the United States and some European countries,in addition to supplementing the loopholes of the prior declaration system and exploiting the law enforcement resources under the existing competition review system,began to use special legislation for large digital platforms to set up "special" rules for platform mergers and acquisitions.China's anti-monopoly regulation of killer acquisition of large digital enterprises is also necessary to take two approaches simultaneously.On the one hand,we should improve the prior declaration system,adjust the competition damage assessment method according to the characteristics of digital enterprise M&A,and introduce the abuse of market dominance into the post-regulation system when necessary.On the other hand,for specific key enterprises,special competition review rules should be set for mergers and acquisitions of super digital platforms,so as to invert the burden of proof of competition injury,fundamentally easing the proof for law enforcement agencies.

Key words: large digital platform enterprises, killer acquisition, start-up enterprises, anti-monopoly regulation