How to split stock earnings?
If he asked you to invest his money with certain objectives which resulted in you buying specific stocks for him with his money, then sell all the stocks which you bought with his money and the capital and profits to him. You may want to calculate the trading fees that you incurred while buying these specific stocks and taxes from the sale of these stocks, withholding them to over the trading fees that you have already paid and the taxes that you might still need to pay. If you traded with his money no different than yours, then I would think of your investment account as a black box. Calculate the initial money that you both invested at the time you added his capital to the account, calculate how much it all is currently worth, then liquidate and return a percentage equal to that of his initial investment. You can account for trading fees and taxes, subtracting by the same percentage. Let's suppose your friend gave your $100 and you invested all of it (plus your own money, $500) into one stock. Therefore, the total investment becomes $100 + $500 = $600. After few months, when you want to sell the stock or give back the money to your friend, check the percentage of profit/loss. So, let's assume you get 10% return on total investment of $600.  Now, you have two choices. Either you exit the stock entirely, OR you just sell his portion. If you want to exit, sell everything and go home with $600 + 10% of 600 = $660. Out of $660, give you friend his initial capital + 10% of initial capital. Therefore, your friend will get $100 + 10% of $100 = $110. If you choose the later, to sell his portion, then you'll need to work everything opposite. Take his initial capital and add 10% of initial capital to it; which is $100 + 10% of $100 = $110. Sell the stocks that would be worth equivalent to that money and that's it. Similarly, you can apply the same logic if you broke his $100 into parts. Do the maths. If you have been a good steward of your friend's money this suggestion will not be too difficult. Pay your friend what his money would have earned in the S&P 500 if you had just invested it in an index fund. Subtract 15% for long-term capital gains. You can use the ticker SPY to see what the price was on the day he gave you the money, versus the price today. If you had helped your friend open an account for himself, you would have given him more than the returns on his money, you would have helped educate him on how to invest for himself.
I agree with the advice given, but I'll add another angle from which to look at it. It sounds like you are already viewing the money used to either pay off the loan early or invest in the market as an investment, which is great. You are wise to think about opportunity cost, but like others pointed out, you are overlooking the risk factor. The way I would look at this is: I could take a guaranteed 6.4% return by paying off the loan or a possible 7% return by investing the money.  If the risk pays off modestly, all you've done is earned 0.6%, with a huge debt still hanging over you. Personally, I would take the guaranteed 6.4% return by paying off the debt, then invest in the stock market. Now this is looking at the investment as a single, atomic pool of money.  But you can split it up a bit.  Let's say the amount of extra disposable income you want to invest with is $1,000/mo.  Then you could pay an extra $500/mo to your student loan and invest the other $500 in  the stock market, or do a 400/600 split, or whatever suits your risk tolerance. You mentioned multiple loans and 6.4% is the highest loan.  What I would do, based on what I value personally, is put every extra penny into paying off the 6.4% loan because that is high.  Once that is done, if the next loan is 4% of less, then split my income between paying extra to it and investing in the market. Remember, with each loan you pay off, the monthly income that previously went to it is now available, and can be used for the next loan or the other goals. One way that is common is to show the value over time of an initial investment, say $10,000.  The advantage of this is that it doesn't show stock price at all, so handles splits well.  It can also take into account dividend reinvestment.  Fidelity uses this for their mutual funds, as can be seen here.  Another option would be to compute the stock price as if the split didn't happen.  So if a stock does a 2:1 split, you show double the actual price starting at that point. I have had this happen a couple of times because of splits or sales of portions of the company.  The general timeline was to announce how the split was to be handled; then the split; then a freeze in purchasing stock in the other company; then a freeze in sales; followed by a short blackout period; then the final transfers to funds/options/cash based on a mapping announced at the start of the process. You need to answer two questions: To determine if the final transactions will make the market move you have to understand how many shares are involved compared to the typical daily volume. There are two caveats: professional investors will be aware of the transaction date and can either ignore the employee transactions or try and take advantage of them; There may also be a mirroring set of transactions if the people left in the old company were awarded shares in your company as part of the sale. If you are happy with the default mapping then you can do nothing, and let the transaction happen based on the announced timeline. It is easy, and you don't have to worry about deadlines. If you don't like the default mapping then you need to know when the blackout period starts, so you don't end up not being able to perform the steps you want when you want.  Timing is up to you. If the market doesn't like the acquisition/split it make make sense to make the move now, or wait until the last possible day depending on which part they don't like. Only you can answer that question. "When you buy a stock, you're really paying for a STREAM of earnings, from now till whenever. The job of an investor is to figure out how large that stream will be in the future. But if the stock price were the same as ""earnings"" (for one year), it would mean that you would get all future earnings for ""free."" That's not likely to happen unless 1) the company is in liquidation,"" meaning ""no future"" and 2) it earned ALL of the money it ever earned in the past year, meaning ""no past."" If there are likely to be any earnings in the future, you will have to pay for those future earnings, over and above what was earned in the most recent year." "The process of borrowing shares and selling them is called shorting a stock, or ""going short.""  When you use money to buy shares, it is called ""going long."" In general, your strategy of going long and short in the same stock in the same amounts does not gain you anything.  Let's look at your two scenarios to see why. When you start, LOOT is trading at $20 per share.  You purchased 100 shares for $2000, and you borrowed and sold 100 shares for $2000.  You are both long and short in the stock for $2000.  At this point, you have invested $2000, and you got your $2000 back from the short proceeds.  You own and owe 100 shares. Under scenario A, the price goes up to $30 per share.  Your long shares have gone up in value by $1000.  However, you have lost $1000 on your short shares.  Your short is called, and you return your 100 shares, and have to pay interest.  Under this scenario, after it is all done, you have lost whatever the interest charges are. Under scenario B, the prices goes down to $10 per share.  Your long shares have lost $1000 in value.  However, your short has gained $1000 in value, because you can buy the 100 shares for only $1000 and return them, and you are left with the $1000 out of the $2000 you got when you first sold the shorted shares.  However, because your long shares have lost $1000, you still haven't gained anything.  Here again, you have lost whatever the interest charges are. As explained in the Traders Exclusive article that @RonJohn posted in the comments, there are investors that go long and short on the same stock at the same time.  However, this might be done if the investor believes that the stock will go down in a short-term time frame, but up in the long-term time frame.  The investor might buy and hold for the long term, but go short for a brief time while holding the long position. However, that is not what you are suggesting.  Your proposal makes no prediction on what the stock might do in different periods of time.  You are only attempting to hedge your bets.  And it doesn't work.  A long position and a short position are opposites to each other, and no matter which way the stock moves, you'll lose the same amount with one position that you have gained in the other position.  And you'll be out the interest charges from the borrowed shares every time. With your comment, you have stated that your scenario is that you believe that the stock will go up long term, but you also believe that the stock is at a short-term peak and will drop in the near future.  This, however, doesn't really change things much.  Let's look again at your possible scenarios. You believe that the stock is a long-term buy, but for some reason you are guessing that the stock will drop in the short-term.  Under scenario A, you were incorrect about your short-term guess.  And, although you might have been correct about the long-term prospects, you have missed this gain.  You are out the interest charges, and if you still think the stock is headed up over the long term, you'll need to buy back in at a higher price. Under scenario B, it turns out that you were correct about the short-term drop.  You pocket some cash, but there is no guarantee that the stock will rise anytime soon.  Your investment has lost value, and the gain that you made with your short is still tied up in stocks that are currently down. Your strategy does prevent the possibility of the unlimited loss inherent in the short.  However, it also prevents the possibility of the unlimited gain inherent in the long position.    And this is a shame, since you fundamentally believe that the stock is undervalued and is headed up.  You are sabotaging your long-term gains for a chance at a small short-term gain." I'm trying to think it out, but I feel like it would be hard to justify using potential profit sources as material for dividends. Especially your example of wine. Wouldn't it be counterintuitive to take a hit to sales, while still having the cost of production? Simply put, 100% stock dividend is 1:1 or 1 for 1 bonus share, as explained above, if you held 100 shares after 1:1 bonus you would have 200 shares (100 original, another 100 as bonus). The impact on the stock price is that the price becomes 1/2 the price of the stock before bonus (supply has doubled). 1:1 bonus is nor exactly like a 2:1 / 2 for 1 stock split, in a split the face value if the share would also go down. In effect, any bonus share is not of any fundamental value to the shareholder, as the companies usually capitalize reserves from previous year/years this way as the value of the company does not change fundamentally. In effect the company is taking your money and giving you shares instead. If you go through the web pages of some online brokers, you will find out that some of them allow you to manage friends/relatives accounts from your account as a trusteer. That should really solve your underlying problem, you will need only one login, etc. (Example: https://www.interactivebrokers.com/ff/en/main.php) If I understand it right it will even allow you to make one trade splitting the cost and returns among the other accounts, but you would have to verify that. Anyways, that will save you a lot of trouble and your broker can probably help you with the legal necessities.