做多和做空都需要做调研，但方法论截然不同，做多是“证实”，优点和缺点都要考量，权衡之下能给出“买入”的评级；做空则是“证伪”，俗称“找茬”，只要找到企业的财务、经营造假证据，“硬伤”一经发现，即可成为做空的理由，类似于“一票否决制”。
先看看浑水的通用手法：
Source: (1 封私信 / 27 条消息) 如何看待浑水做空瑞幸（2020）这一事件？ – 知乎
MW is short $LK. We received unattributed 89-page report alleging $LK is a fraud: "number of items per store per day was inflated by at least 69% in 2019 3Q and 88% in 2019 4Q, supported by 11,260 hours of store traffic video" We view the work as credible. https://t.co/N3rXlrvfcZ
— MuddyWatersResearch (@muddywatersre) January 31, 2020