There are three sentiments. The first is that since they were given to you, the cost basis is zero. The second is that since this was an IPO and represented a conversion of ownership in the company to ownership in stock, then the IPO price is the cost basis You can find the IPO price on the internet fairly easily. The third is that a percentage of the payments you made to cover the cost of your insurance up to the point of the IPO can be used to show your cost basis for the stock.
The first one is the easiest and the most likely to not raise red flags with the IRS. The second has been fought in court and won. It is doubtful that the IRS would take notice of this method, but I would put money aside to cover the tax just in case they challenge you. I have heard of one case of someone doing the third option, but I don't know if it was successful or not. This would definitely raise red flags with the IRS so be prepared to fight it.
Thank you for your explanation, I also have the same question on the 77 shares I received. Do you know what is considered the IPO date? Perhaps I am just stupid, but have not been able to figure it out on line. Thanks, and merry holidays.