How many BitCoins are gone forever ??? What would be the current market cap excluding lost bitcoins ???

Four Million Bitcoins are gone Forever.

New research by Chainanalysis, a digital forensics firm that studies the Bitcoin Blockchain, showed that 3.79 mln Bitcoins are already lost. This is on the high estimate of the study's finding, with their low estimate still sitting at an astonishing 2.78 mln. This makes the percentage of lost coins based on what has been mined today to be at between 17 to 23 percent.

Where have they gone?

According to a breakdown supplied by Chainanalysis, their research seems to be quite thorough and a little more than just speculation.

In their segmentation of coins that have been lost in different ways, they have broken it down into coins mined in 2017 - which they believe are still all intact and available. It makes sense that there would be more caution in 2017 with the value of fractions of coins worth huge amounts.

When they refer to strategic investments, they are looking at people who have been holding their coins for a very long time, and thus are perhaps not lost, rather just growing in a stagnant position.