<prompt> Human: So were finally coming up to presenting an offer on our first home. We were promised a gift of 20k to help with a down payment from my SOs parents. They have since updated the offer to 50k as an investment on the home. They would take the percentage increase in value based on purchase price on their 50k investment minus the 20k gift. Were looking at a 350k home. If we end up selling at say 450k, we would owe her parents 44k. This being our first home, were in it for 5-10 years at least and the increased down payment will definitely help us short and long term. They have asked me to write up a letter stating the conditions noted above and we will all sign it. They really are wonderful people and they do have the best intentions. I just want to make sure Im not getting into an awful deal somehow or if I overlooked something.How sound is the deal and are there other things I should consider?  <response>: Im not sure of the rules in Canada, but here in the US, youre required to have the gift-giver sign a letter stating that the money is a gift and does not have to be repaid. If the money has to be repaid in the future, its not a gift, its a loan -- essentially a second mortgage -- and your lending institution will want to know that. Youll definitely want to talk to someone knowledgeable about this. I thought about suggesting a similar arrangement to my parents when I bought my first home, but I decided against it -- I didnt want to introduce additional complications to buying a house. 