Investing.com - Financial regulators, investment pros and even crypto enthusiasts have all warned about the perils of initial coin offerings. Now, there's reason to believe that concerns about their riskiness are well founded.About half of the 902 crowdsales ICOs in 2017 failed, according to a survey by Bitcoin.com.The cryptocurrency site analyzed ICOS tracked by TokenData, and discovered that 276 had failed after fundraising. Another 142 failed before fundraising. Together, 46% didn't survive. Bitcoin.com says the total funding involved in the failed ICOs was $233 million. Many of the ICOs raised no money. Several raised more than $10 million.It's unclear what percentage of the failed ICOs were scams or simply poorly executed launches. Bitcoin.com did describe many of them as "sketchy."