I once played a (somewhat crazy) game of Monopoly where there were too many players, so not enough properties to go around. I ended up with close to zero property but lots of cash. So I made an "investment" in another player. She had great properties (the dark greens) but very little cash; I gave her a couple thousand dollars to build with the agreement that I would get a certain percentage of all income from those properties (I believe it was a 50/50 split) and I would not need to pay if I landed on one of the properties in question. Is this a legal deal? We considered it a form of trading -- I gave her money and in return I would get money in the future.
From the Official Monopoly Rules by Hasbro (my emphasis):
Money can be loaned to a player only by the Bank and then only by mortgaging property. No player may borrow from or lend money to another player
Any exchange of money for future considerations is a form of loan, so by the official monopoly rules your actions are illegal. One is always allowed to invent a new game based on an existing one, through the use of common agreement on house rules, but one cannot then meaningfully call it by the name Monopoly.
While you are technically allowed to make such a deal, due to the fact that trading allows you to give another player money; there is nothing in the rules that would enforce your opponent to keep her end of the deal. If you later landed on the property in question, she would be fully within her rights within the rules to ask you to pay, and you would have to pay according to the rules. Similarly, if she makes money from someone else on that property, there is no rule that requires her to give you part of that money.
So as long as you fully trust her to do what she says in the future, you would be allowed within the rules to do this.
I found this answer to be almost perfect for your question. I have copied it below for easy reference.
Pretty much, it says you CAN invest in people, but there are certain rules that still have to be followed. Additionally, there is nothing binding them to you or vice versa. Unless you specify everything in your own set of house rules, it's a risky way to play.
Going by the official rules, you don't have a choice whether to collect rent or not:
When you land on property owned by another player, the owner collects rent from you...
This doesn't give the property owner any choice in the matter, they simply do collect rent.
However, you could offer immunity as follows:
- The player who lands on your property pays rent.
- You immediately pay them back the amount they just paid.
To do this, you'll have to be able to give money to another player. There is a rule forbidding loans between players:
No player may borrow from or lend money to another player.
but a gift is not the same as a loan. Another way to give money to another player is to sell them an unimproved property for $0, then buy it back for the amount you wish to give them. This is allowed by a different rule:
Unimproved properties, railroads and utilties (but not buildings) may be sold to any player as a private transaction for any amount...
All of this comes with a caveat: You can't do anything to force someone to grant you immunity, it's entirely up to them choosing to act in good faith.
I have played this way before by either
- Investing in another player's land to build property
- Receiving investment from a player to build property on my land
There is nothing written in the rule book about investment. so i assume that if it doesn't say "you can't" then it is allowed.
The following issues arise:
If one of the players land on a different (concurrent player's) property and doesn't have cash to pay off, then selling properties was a big issue. We had an actual written contract on what happens if that occurs and how we sell off a property.
Having multiple investments in different players or having multiple investors on your land. Here we applied the rule where the land owner must have 51% of the invested land value, if someone else has more than 51% of the shares then land ownership is transferred to that player. also whoever has the 51% percent makes the decision of selling property/land, put on mortgage and etc. When a player decides to invest in more property (increase number of houses or upgrade to hotels) the other player(s) must invest too in order to keep their share % in order to have a respective return of investment. When one is in need of cash he must offer to sell shares to the other investors first before selling to bank.
What happens when all the other teams/players go bankrupt? How do we share the lands? What we did was either we win as a team or we divide property on mutual agreement or we sell property and give out cash respectively to players who invested and the land owner has the land owned without property (unless he decides to invest himself) and continue the game (although 2 players playing head-to-head is slow and boring).
3.1 Also a sub issue. When they sell property back to bank the value is half of the original purchased price. This means the value of the shares is not increased. So the land owner has more advantage should they decide to sell property.
It is very difficult to explain concept of investments and shares to players who are not familiar with these business concepts. Explaining these rules and concepts takes 60-80% of overall playing time. (Arguments and even fights arise when one of the players goes bankrupt).