What is the difference between playing the lotto, lottery, investing in the stockmarket, 401K?

When you invest in the stockmarket and have a 401k are you not taking a risk just like gambling. I do not see the difference. Does the Bible specifically state that it is a transgression or sin to gamble? If the Bible does not say it how can man say it is sin. Is not sin a transgression or a missing of the mark (God's Law)?