As I mentioned in part 1 of this guide, 18XX games are essentially two games rolled into one: the stock market game, and the operations game.
Stock market mechanics can vary wildly from one 18XX game to the next: in fact, the 18XX series is split into two branches based upon the fundamental behavior of the stock market.
In most 18XX, each railroad has 10 shares of stock - one 20% presidential certificate (worth 2 shares), and eight 10% certificates (worth 1 share). Players can found new railroads during a stock round by purchasing the presidential certificate - usually done by choosing a "par" value for the railroad, and paying twice that amount to the bank. After a pre-determined number of shares has been purchased (typically 5 or 6), the railroad is "floated", and may begin operations during the operating rounds.
The 1829 branch games tend to have a one dimensional stock market - a single row of spaces with increasing values on them to represent the current monetary value of each share of stock in a railroad. In these games, it's unusual for a stock sale to affect the railroad's value - the primary movement of railroad share prices is based upon whether a railroad pays dividends (moving to the right, increasing share value) or doesn't (moving to the left, decreasing share value).
The 1830 branch games tend to have a two dimensional stock market - a grid of spaces, where moving up (increasing value) or down (decreasing value) comes into play. It is these games were selling shares affects share value by decreasing it, and selling out (having all 10 shares owned by players at the end of the stock round) increases it.
While there are certainly exceptions to the above, the above is the most common amongst 18XX games. Some of the more frequent differences seen regarding the stock portion of the game are highlighted here:
1) Each railroad in 18XX, once floated, receives a starting cash allotment. Some 18XX games give 10 times the "par" value mentioned above, leaving the remaining shares in what's called an "IPO", or Initial Public Offering. Other 18XX games give only the cash for the shares as they are purchased, tightening the cash flow for the railroad until the remaining shares are purchased, but leaving the remaining shares in the railroads treasury where they will pay their dividends.
2) Some 18XX games have what are called "Minor" railroads, that are treated as a single share of stock giving 100% ownership to the purchasing player. These Minors do not have a share value, and don't have the option on whether to pay dividends or not - 50% of the Minor's revenue is paid to the owner, and the other 50% is paid to the Minor's treasury. 18OE is one such game. It is common in these games for the Minors to be absorbed by other Railroads later in the game, exchanging their assets (cash, tokens, and trains) for a share of stock in the absorbing Railroad.
3) Some 18XX games allow what's called "splitting" - where a Railroad can pay half of its revenue out to shareholders, and keep the other half in the treasury. In most cases, as long as the portion of revenue paid to shareholders exceeds the Railroad's current share value, the stock will still increase in value (moving to the right on the stock market).
While this guide doesn't touch on the finer points of strategy in the stock market game, suffice it to say that the richness of diversity in different 18XX games creates a different challenge depending upon which game you choose to play.
Check back next week, where I'll talk about the operations side of 18XX!
The frequently mentioned division of 18xx games into "1829" and "1830" branches doesn't really work and this is especially true when it comes to stock markets. It is certainly true that there is a family of games deriving from 1830 that have the behaviour that Mark describes for that family. There are also many games that some people place in the 1830 branch that have utterly placid stock-markets.
Several of the games in which minor companies fold into major ones tend to be in that class. (e.g. 1861, 18EU, 18Ardennes), but this is not universal. As a counter-example, 1817 is possible the most financially volatile 18xx so far developed.
One key distinction that Mark doesn't mention is whether the Director's share of a company may be sold to the open market or bank pool, so that no-one is running this company. That distinction is what for me defines the 1825 branch of games - 1825, 1853, 1860 and maybe one or two others.
Another consideration is whether a company's share price can increase more than one space when it pays a dividend - a feature known as multi-jumping - or whether, as in most games, the price moves only one space.
I believe there are now many overlapping sub-families of 18xx rather than just the 1829 vs 1830 distinction. It can all be rather confusing to beginners and to be honest the best approach is probably to dive into one and try it, just bearing in mind that there are other 18xx games out there which will be very different.