In the public equities markets, a lot of amateurs lose money making assumptions based on lazy analyses of Form 4 filings. There are a variety of reasons insider

In the public equities markets, a lot of amateurs lose money making assumptions based on lazy analyses of Form 4 filings. There are a variety of reasons insiders sell which have absolutely nothing to do with the health of their companies. Trying to glean meaningful and profitable insight from these filings is a lot more difficult than you suggest. The same dynamic applies to startup investments, particularly in the early stages. There are any number of reasons why an investor may not make a follow-on investment. These range from the personal finances of the investor to conflicts that have emerged in the investor's portfolio. More importantly, at the seed stage, even the most successful angel investors (if they're honest) will readily admit that it's damn near impossible to tell the future winners from the losers, and anybody who has been investing actively can tell stories about ones that got away, so there's limited value in playing follow the leader. Signaling is a bigger issue in later stage financings, but there too, if you make assumptions without digging deeper (something any good investor does), you're bound to draw the wrong conclusions.