Dates of ERC20 tokens transactions

Question

I'm an individual who is interested to ICOs which are selling ERC20 tokens.

My question is related to an issue that, for most of the ERC20 tokens, the dates of transactions do not fall within the ICO periods.

For example, Blockchain.io sold "BCIO" token during its ICO period which is between 27th Sep 2018 to 25th Oct 2018.

However, the initial transaction of BCIO in etherscan.io here starts from 23rd Nov 2018 which is after the ICO period. (See the last page in the link)

Could anyone please let me know why there are this kind of delays in nearly every transactions of ERC20 tokens? Is there a delay or is etherscan.io not an accurate explorer?

Thank you for your time.

Answer 1

During that year, many ICOs (as far as I remember), used to follow an approach where they collected funds and defined allocations in a separate contract or multiple (think presale, mainsale, etc. i.e. different contracts) and then they had a date where they would mint and allocate tokens to the investors based on information related to their ether contributions during the sale periods.

Hell, I've even seen ICOs which have collected ether through centralised "ICO Dashboards" to a personal wallet and then manually distributed allocations based on excel sheets and distribution date promises. Here, they only created an ERC20 compliant token contract and manually transferred tokens at a given date, very odd indeed.