Buying a house 50/50
This question is really a variation of rent vs buy.  Try looking at it this way - If you bought it 50/50 and rented it out, what would you both get? Now, moved in, you are effectively collecting that rent, but half is your own money, half is from the partner.  Is the half you are getting the from the partner equal to 1/4 of the mortgage. This sounds convoluted, but once you spell all the numbers out, it would be clear.  Without the deal as you present it, you'd be paying the partner to 'live in his half.' I don't like it using percentages makes no sense.  Find out what market value is for rent and pay 1/2 of that to your partner, adjust annually.   You partner should be protected from inflation if he is going to invest in real estate.
"The current mortgaged owner would typically not have the right to sell any portion of the house without approval from the bank. The bank doesn't ""own"" the house through the mortgage, but they do have a series of rights that, in some cases, look similar to ownership.  Remember that a mortgage is just a loan that uses a house as collateral, to reduce the risk to the lender in the event of default. If it was just a personal loan, without collateral, then there would be a much higher risk of default (and therefore the interest rate would be closer to 20% than 2%). But because the loan was taken with collateral, that collateral can't be sold without the bank's permission. If the bank allowed this to happen, then one risk would be exactly as you say - that the mortgagee stops paying the bank, and the bank no longer is able to recover the full value of the loan on selling the remaining 50% of the house owed as collateral." "Accounting for this properly is not a trivial matter, and you would be wise to pay a little extra to talk with a lawyer and/or CPA to ensure the precise wording. How best to structure such an arrangement will depend upon your particular jurisdiction, as this is not a federal matter - you need someone licensed to advise in your particular state at least. The law of real estate co-ownership (as defined on a deed) is not sufficient for the task you are asking of it - you need something more sophisticated. Family Partnership (we'll call it FP) is created (LLC, LLP, whatever). We'll say April + A-Husband gets 50%, and Sister gets 50% equity (how you should handle ownership with your husband is outside the scope of this answer, but you should probably talk it over with a lawyer and this will depend on your state!).  A loan is taken out to buy the property, in this case with all partners personally guaranteeing the loan equally, but the loan is really being taken out by FP. The mortgage should probably show 100% ownership by FP, not by any of you individually - you will only be guaranteeing the loan, and your ownership is purely through the partnership. You and your husband put $20,000 into the partnership. The FP now lists a $20,000 liability to you, and a $20,000 asset in cash. FP buys the $320,000 house (increase assets) with a $300,000 mortgage (liability) and $20,000 cash (decrease assets). Equity in the partnership is $0 right now. The ownership at present is clear. You own 50% of $0, and your sister owns 50% of $0. Where'd your money go?! Simple - it's a liability of the partnership, so you and your husband are together owed $20,000 by the partnership before any equity exists. Everything balances nicely at this point. Note that you should account for paying closing costs the same as you considered the down payment - that money should be paid back to you before any is doled out as investment profit! Now, how do you handle mortgage payments? This actually isn't as hard as it sounds, thanks to the nature of a partnership and proper business accounting. With a good foundation the rest of the building proceeds quite cleanly. On month 1 your sister pays $1400 into the partnership, while you pay $645 into the partnership. FP will record an increase in assets (cash) of $1800, an increase in liability to your sister of $1400, and an increase in liability to you of $645. FP will then record a decrease in cash assets of $1800 to pay the mortgage, with a matching increase in cost account for the mortgage. No net change in equity, but your individual contributions are still preserved. Let's say that now after only 1 month you decide to sell the property - someone makes an offer you just can't refuse of $350,000 dollars (we'll pretend all the closing costs disappeared in buying and selling, but it should be clear how to account for those as I mention earlier). Now what happens? FP gets an increase in cash assets of $350,000, decreases the house asset ($320,000 - original purchase price), and pays off the mortgage - for simplicity let's pretend it's still $300,000 somehow. Now there's $50,000 in cash left in the partnership - who's money is it? By accounting for the house this way, the answer is easily determined. First all investments are paid back - so you get back $20,000 for the down payment, $645 for your mortgage payments so far, and your sister gets back $1400 for her mortgage payment. There is now $27,995 left, and by being equal partners you get to split it - 13,977 to you and your husband and the same amount to your sister (I'm keeping the extra dollar for my advice to talk to a lawyer/CPA). What About Getting To Live There? The fact is that your sister is getting a little something extra out of the deal - she get's the live there! How do you account for that? Well, you might just be calling it a gift. The problem is you aren't in any way, shape, or form putting that in writing, assigning it a value, nothing.  Also, what do you do if you want to sell/cash out or at least get rid of the mortgage, as it will be showing up as a debt on your credit report and will effect your ability to secure financing of your own in the future if you decide to buy a house for your husband and yourself?  Now this is the kind of stuff where families get in trouble. You are mixing personal lives and business arrangements, and some things are not written down (like the right to occupy the property) and this can really get messy. Would evicting your sister to sell the house before you all go bankrupt on a bad deal make future family gatherings tense? I'm betting it might. There should be a carefully worded lease probably from the partnership to your sister. That would help protect you from extra court costs in trying to determine who has the rights to occupy the property, especially if it's also written up as part of the partnership agreement...but now you are building the potential for eviction proceedings against your sister right into an investment deal? Ugh, what a potential nightmare! And done right, there should probably be some dollar value assigned to the right to live there and use the property. Unless you just want to really gift that to your sister, but this can be a kind of invisible and poorly quantified gift - and those don't usually work very well psychologically. And it also means she's going to be getting an awfully larger benefit from this ""investment"" than you and your husband - do you think that might cause animosity over dozens and dozens of writing out the check to pay for the property while not realizing any direct benefit while you pay to keep up your own living circumstances too? In short, you need a legal structure that can properly account for the fact that you are starting out in-equal contributors to your scheme, and ongoing contributions will be different over time too. What if she falls on hard times and you make a few of the mortgage payments? What if she wants to redo the bathroom and insists on paying for the whole thing herself or with her own loan, etc? With a properly documented partnership - or equivalent such business entity - these questions are easily resolved. They can be equitably handled by a court in event of family squabble, divorce, death, bankruptcy, emergency liquidation, early sale, refinance - you name it. No percentage of simple co-ownership recorded on a deed can do any of this for you. No math can provide you the proper protection that a properly organized business entity can. I would thus strongly advise you, your husband, and your sister to spend the comparatively tiny amount of extra money to get advice from a real estate/investment lawyer/CPA to get you set up right. Keep all receipts and you can pay a book keeper or the accountant to do end of the year taxes, and answer questions that will come up like how to properly account for things like depreciation on taxes. Your intuition that you should make sure things are formally written up in times when everyone is on good terms is extremely wise, so please follow it up with in-person paid consultation from an expert. And no matter what, this deal as presently structured has a really large built-in potential for heartache as you have three partners AND one of the partners is also renting the property partially from themselves while putting no money down?  This has a great potential to be a train wreck, so please do look into what would happen if these went wrong into some more detail and write up in advance - in a legally binding way - what all parties rights and responsibilities are." The calculations you suggest have some issues, but I think they are not necessary to answer the question: It sounds like you are buying the house either way. So the question really is simply whether to pay toward your house first or your loan first.  In that case, the answer is simple: pay whichever has the highest interest rate first.  Make the minimum payment on the other until the first is paid off.  Remember this and make it your mantra for the rest of your life.  If you have any debts (such as credit cards) that charge a rate higher than the two options you have presented, do them first. Now, be careful as you compute the interest rates.  Most likely you can deduct interest on your mortgage, so its effective interest rate is lower [it is (1-T)*R instead of R, where T is your marginal tax rate]. For a while, the cost of mortgage insurance will make your effective mortgage rate artificially high, but it sounds like you intend to get to that 20% hurdle pretty fast, so my guess is that this is not a big factor. Congratulations on your bonus and good luck with your new home. Split the money 50/50. Split the costs 50/50.  Prioritize your relationship over a couple of dollars here and there. I've investigated this, and banks are willing to offer a deal similar to what you ask. You would take out a securities-backed loan, which provides you with the down payment on the property. For the remainder, you take out a regular mortgage.  JAGAnalyst wonders why banks would accept this. Simple: because there's money to be made, both on the securities-backed loan and the mortgage. Both parts of the deal are financially sound from the banks perspective. Now, the 20% number is perhaps a bit low. Having 20% of the value in shares means you'd be able to get a loan for 50% of that, so only a 10% downpayment. It would be good to know which country you are in? You are basically on the right track with your last point. Usually when you buy your first property you need to come up with a deposit and then borrow the remainder to have enough to purchase the property. In most cases (and most places) the standard percentage of loan to deposit is 80% to 20%. This is expressed as the Loan to Value Ratio (LVR) which in this case would be 80%. (This being the amount of the loan to the value of the property). Some banks and lenders will lend you more than the 80% but this can usually come with extra costs (in Australia the banks charge an extra percentage when you borrow called Loan Mortgage Insurance (LMI) if you borrow over 80% and the LMI gets more expensive the higher LVR you borrow). Also this practice of lending more than 80% LVR has been tightened up since the GFC. So if you are borrowing 80% of the value of the property you will need to come up with the remainder 20% deposit plus the additional closing costs (taxes - in Australia we have to pay Stamp Duty, solicitor or conveyancing fees, loan application fees, building and pest inspection costs, etc.). If you then want to buy a second property you will need to come up with the same deposit and other closing costs again. Most people cannot afford to do this any time soon, especially since the a good majority of the money they used to save before is now going to pay the mortgage and upkeep of your first property (especially if you used to say live with your parents and now live in the property and not rent it out). So what a lot of people do who want to buy more properties is wait until the LVR of the property has dropped to say below 60%. This is achieved by the value of the property going up in value and the mortgage principle being reduced by your mortgage payments. Once you have enough, as you say, collateral or equity in the first property, then you can refinance your mortgage and use this equity in your existing property and the value of the new property you want to buy to basically borrow 100% of the value of the new property plus closing costs. As long as the LVR of the total borrowings versus the value of both properties remains at or below 80% this should be achievable. You can do this in two ways. Firstly you could refinance your first mortgage and borrow up to 80% LVR again and use this additional funds as your deposit and closing costs for the second property, for which you would then get a second mortgage. The second way is to refinance one mortgage over the two properties. The first method is preferred as your mortgages and properties are separated so if something does go wrong you don't have to sell everything up all at once. This process can be quite slow at the start, as you might have to wait a few years to build up equity in one property (especially if you live in it). But as you accumulate more and more properties it becomes easier and quicker to do as your equity will increase quicker with tenants paying a good portion of your costs if not all (if you are positively geared). Of course you do want to be careful if property prices fall (as this may drastically reduce your equity and increase your total LVR or the LVR on individual properties) and have a safety net. For example, I try to keep my LVR to 60% or below, currently they are below 50%. "You are suggesting that a 1% return per month is huge. There are those who suggest that one should assume (a rule of thumb here) that you should assume expenses of half the rent. 6% per year in this case. With a mortgage cost of 4.5% on a rental, you have a forecast profit of 1.5%/yr. that's $4500 on a $300K house. If you buy 20 of these, you'll have a decent income, and a frequently ringing phone. There's no free lunch, rental property can be a full time business. And very lucrative, but it's rarely a slam dunk.  In response to OP's comment - First, while I do claim to know finance fairly well, I don't consider myself at 'expert' level when it comes to real estate.  In the US, the ratio varies quite a bit from area to area. The 1% (rent) you observe may turn out to be great. Actual repair costs low, long term tenants, rising home prices, etc. Improve the 1.5%/yr to 2% on the 20% down, and you have a 10% return, ignoring appreciation and principal paydown. And this example of leverage is how investors seem to get such high returns. The flip side is bad luck with tenants. An eviction can mean no rent for a few months, and damage that needs fixing. A house has a number of long term replacement costs that good numbers often ignore. Roof, exterior painting, all appliances, heat, AC, etc. That's how that ""50% of rent to costs"" rule comes into play." Sorry, I don't think a bounty is the issue here. You seem to understand LTV means the bank you are talking to will lend you 60% of the value of the home you wish to purchase. You can't take the dollars calculated and simply buy a smaller house.  To keep the numbers simple, you can get a $600K mortgage on a $1M house. That's it. You can get a $540K mortgage on a $900K house, etc.  Now, 60% LTV is pretty low. It might be what I'd expect for rental property or for someone with bad or very young credit history. The question and path you're on need to change. You should understand that the 'normal' LTV is 80%, and for extra cost, in the form of PMI (Private Mortgage Insurance) you can even go higher. As an agent, I just sold a home to a buyer who paid 3% down.  The way you originally asked the question has a simple answer. You can't do what you're asking. Even post meltdown, there are banks that will lend money based on a low loan to value, so 50% might not be a problem. But such loans come at a price. The current 30 year fixed rated is 4.5% or so, but you might see quite a bit higher than this on the loan. While I agree with the existing bulk of comments and answers that you can't tell the lender the $7k is a gift, I do think you might have luck finding a mortgage broker who can help you get a loan as a group.  (You might consider as an LLC or other form of corporation if no one will take you otherwise.)  That is, each of you will be an owner of the house and appear on the mortgage.  IIRC, as long as the downpayment only comes from the collective group, and the income-to-debt ratio of the group as a whole is acceptable, and the strongest credit rating of the group is good, you should be able to find a loan.  (You may need a formal ownership agreement to get this accepted by the lender.)  That said, I don't know if your income will trump your brother's situation (presumably high debt ratio or lower than 100% multiplier on his income dues to its source), but it will certainly help. As to how to structure the deal for fairness, I think whatever the two of you agree to and put down in writing is fine.  If you each think you're helping the other, than a 50/50 split on profits at the sale of the property seems reasonable to me.   I'd recommend that you actually include in your write up a defined maximum period for ownership (e.g. 5yr, or 10yr, etc,) and explain how things will be resolved if one side doesn't want to sell at that point but the other side does. Just remember that whatever percentages you agree to as ownership won't effect the lender's view of payment requirements.  The lender will consider each member of the group fully and independently responsible for the loan.  That is, if something happens to your brother, or he just flakes out on you, you will be on the hook for 100% of the loan.  And vice-versa.  Your write up ought to document what happens if one of you flakes out on paying agreed upon amounts, but still expects there ownership share at the time of sale. That said, if you're trying to be mathematically fair about apportioning ownership, you could do something like the below to try and factor in the various issues into the money flow: The above has the benefit that you can start with a different ownership split (34/66, 25/75, etc.) if one of you wants to own more of the property. "The Solicitor involved up front should be able to place constrictions as your suggesting.  I think you should look carefully at the desired wording. You deserve a return on your £100k. Say, the day after you buy (this is hypothetical, please bear with me) a developer says he needs the property and will give you £460k. Your wording here says you get £100k, and then, after the mortgage split £230k, but it seems more reasonable that your deposit doubles to £200k, the remaining £260k pays the mortgage, and the £130k left is split, £65k each.  My method accounts for the value of your £100k. Some would ask, why not apply the mortgage rate to that deposit? Because the home value may grow at a different rate. In my opinion, it's fair to apply the home value growth to the £100k deposit.  ""Fair"" means different things to different people. This is my opinion, and a suggestion. Consider it, and do what you and your partner wish. Use a solicitor. Put it in writing." The assumption that house value appreciates 5% per year is unrealistic. Over the very long term, real house prices has stayed approximately constant. A house that is 10 years old today is 11 years old a year after, so this phenomenon of real house prices staying constant applies only to the market as a whole and not to an individual house, unless the individual house is maintained well. One house is an extremely poorly diversified investment. What if the house you buy turns out to have a mold problem? You can lose your investment almost overnight. In contrast to this, it is extremely unlikely that the same could happen on a well-diversified stock portfolio (although it can happen on an individual stock). Thus, if non-leveraged stock portfolio has a nominal return of 8% over the long term, I would demand higher return, say 10%, from a non-leveraged investment to an individual house because of the greater risks. If you have the ability to diversify your real estate investments, a portfolio of diversified real estate investments is safer than a diversified stock portfolio, so I would demand a nominal return of 6% over the long term from such a diversified portfolio. To decide if it's better to buy a house or to live in rental property, you need to gather all of the costs of both options (including the opportunity cost of the capital which you could otherwise invest elsewhere). The real return of buying a house instead of renting it comes from the fact that you do not need to pay rent, not from the fact that house prices tend to appreciate (which they won't do more than inflation over a very long term). For my case, I live in Finland in a special case of near-rental property where you pay 15% of the building cost when moving in (and get the 15% payment back when moving out) and then pay a monthly rent that is lower than the market rent. The property is subsidized by government-provided loans. I have calculated that for my case, living in this property makes more sense than purchasing a market-priced house, but your situation may be different. I don't have a solid data-backed answer, but this is too lengthy for a comment. I've read that on average, about 1-2% is what you can get as a cash discount on a home purchase, all else being equal, but no hard data to back that.  In certain situations it makes sense for a cash discount to be much greater than that, for instance, if the seller is in a hurry to close and your cash offer has no inspection clause. Similarly, if a house has been re-listed after a sale fell through you might get a greater cash-discount, or if an owner just over-values the advantages of a cash-offer. Anecdotally, I had a neighbor take a cash offer 5% below asking and they had multiple offers at asking, they took the cash offer so they could close faster (15 days). Also, I've lost out to a cash offer, also at 5% below asking, and they also had a short-closing period and no-inspection, my offer was over asking on that one, so total cash discount > 5%. There can be more volatility in the luxury home market, but I wouldn't guess that changes the cash vs financed evaluation much.  Would love to see if anyone finds a good source, but even if they do, an average is only so helpful. Presumably this house is a great deal for you for some reason if you are willing to go to great lengths such as these to acquire it. I suggest you have your father purchase the house with cash, then you purchase the house from him. You might want to discuss this with the title company, it's possible that there are some fees that they will waive if you close both sales through them in a short period of time. If the home will appraise for a higher amount than purchase, then you may be able to get a mortgage without a significant down-payment. If not, then you will need to owe your father at least the amount of the down-payment at closing time. You and your husband are fronting all the money upfront. I'm guessing this will cost you around 67,000 once closing costs and fees are included. So obviously you would be hundred percent owners at the beginning. You'll then pay 31% of the mortgage and have your sister pay the remaining 69%. This puts your total investment at the end at 67k + 74.4k + 31% of interest accrued, and your sisters total investment at 165.6k+69% of interest accrued. If you hold the full length of the mortgage, your sister will have invested much more than you( assuming 30 year fixed rate, and 3.75%, she'd pay 116.6k in interest as opposed to your 49.6k) She will have spent 282.2k and y'all will have spent 191k. However if you sell early, your percentage could be much higher.  These calculations don't take into account the opportunity cost of fronting all the cash. It could be earning you more in the stock market or in a different investment property. Liability also could be an issue in the case of her not being able to pay. The bank can still come after you for the whole amount. Lastly and most importantly, this also doesn't include the fact that she will be living there and y'all will not. What kind of rent would she be paying to live in a similar home? If it is more than 1400, you will basically be subsidizing her living, as well as tying up funds, and increasing your risk exposure. If it is more than 1400, she shouldn't be any percent owner.