What a great launch! Thank you everyone for your positive words, it's great to see lots of players enjoying the game.
Now that things have calmed down a bit, I've created a test_public branch which contains the new Stock Market feature. If you'd like to help test it out, you can switch to that branch under Properties -> Betas. Note the Stock Exchange location will only appear on a new map.
If no issues are reported in 1-2 days, I will release the update to everyone else and write a proper update post.