Is there any kind of unsecured stock loan?
buy an option, they cost less and let you buy shares in the future at the price you see now. only if you plan to buy more than 100 shares of the stock at that future date though. better learn how to use options strategically first, which I won't go into. but this is indeed their purpose. In the U.S. it is typical that a stock brokerage account can be set up to buy stock with up to half the cost being borrowed from the broker.  This is called a margin account.  The stock purchased must remain in the account until sold (or the loan is paid off), as it serves as built-in collateral for the loan.  If the market price for the stock goes down too much, you will be required to add money, or the stock will be sold to cover the loan. See this question for some more information.
There's no standard formula. You can compare the going rates on the market for unsecured LOCs and take that as the starting anchor. Unsecured lines of credit run in the US at about 8-18%. Your risk should be reflected in the rate, and I see no reason why the rate would change throughout the loan. As to the amount of principal changing? Just chose one of the standard compounding options - daily (most precise, but most tedious to calculate), monthly average balance, etc. If you have no credit score it is generally far easier and more affordable to establish credit the cheapest way possible, which is usually in the form of a small credit card (student card if you are a student, low credit line unsecured, or even secured if you need). Your local bank/credit union will usually be keen to offer you something to start out, but you can also apply online to some of the major credit card vendors. As always, look out for annual fees, etc. In general, trying to get a larger loan to establish credit will cost you a lot as you will not qualify for any legitimate 0% or ultra-low APR car loans - those are reserved for people with established and generally pretty good credit. I expect you'll find a car loan that will have a lower APR than you could get investing your money otherwise - especially if you do not have established excellent credit - to simply be a phantom (you won't find it), and even if you could it is more risky than it is worth. Furthermore, if establishing credit is important to you (such as for buying a house down the road), you can build an excellent credit score without ever having a car loan. So you don't have to buy a car on borrowed money just to hope to get approved for a house some day - it's just not a requirement. Finally, I urge you to make a decision on the best car for you in your situation, ignoring the credit score - especially if you are more than 3-5+ years away from buying a house. Everything else about buying a car is more important - the actual cost of the car, year, mileage, suitability for your needs, gas mileage, maintenance and insurance costs, etc.  Then, at the very end of your decision making process, ensure that buying the car would not put you dangerously low on savings by squeezing your emergency fund. Decide if you really need a loan or as expensive of a car, considering the costs over the expected life of you owning the car (or at least the next 2-5 years). Never get trapped into just thinking about monthly payments, which hide the true cost of loans and buying beyond what you can afford to purchase today. They're exchange traded debt, basically, not funds. E.g. from the NYSE: An exchange-traded note (ETN) is a senior unsecured debt obligation designed to track the total return of an underlying market index or other benchmark, minus investor fees. Whereas an ETF, in some way or another, is an equity product - which doesn't mean that they can only expose you to equity, but that they themselves are a company that you buy shares in.  FCOR for example is a bond ETF, basically a company whose sole purpose is to own a basket of bonds.  Contrast that to DTYS, a bear Treasury ETN, which is described as  The ETNs are unsecured debt obligations of the issuer, Barclays Bank PLC, and are not, either directly or indirectly, an obligation of or guaranteed by any third party. Also from Barclays site: Because the iPath ETNs are debt securities, they do not have any voting rights. FCOR on the other hand is some sort of company owned/managed by a Fidelity trust, though my EDGAR skills are rusty. AGREEMENT made this 18th day of   September, 2014, by and between Fidelity Merrimack Street Trust, a Massachusetts business trust which may issue one or more series of shares of beneficial interest (hereinafter called the Trust), on behalf of Fidelity Corporate   Bond ETF (hereinafter called the Fund), and Fidelity Investments Money Management, Inc., a New Hampshire corporation (hereinafter called the Adviser) as set forth in its entirety below. A security is a class of financial instrument you can trade on the market.  A share of stock is a kind of security, for example, as is a bond. In the case of your mortgage, what happens: You take out a loan for $180k.  The loan has two components. a.  The payment stream (meaning the principal and the interest) from the loan b.  The servicing of the loan, meaning the company who is responsible for accepting payments, giving the resulting income to whomever owns it. Many originating banks, such as my initial lender, do neither of these things - they sell the payment stream to a large bank or consortium (often Fannie Mae) and they also sell the servicing of the loan to another company. The payment stream is the primary value here (the servicing is worth essentially a tip off the top).  The originating bank lends $180k of their own money.  Then they have something that is worth some amount - say $450k total value, $15k per year for 30 years - and they sell it for however much they can get for it.  The actual value of $15k/year for 30 years is somewhere in between - less than $450k more than $180k - since there is risk involved, and the present value is far less.  The originating bank has the benefit of selling that they can then originate more mortgages (and make money off the fees) plus they can reduce their risk exposure. Then a security is created by the bigger bank, where they take a bunch of mortgages of different risk levels and group them together to make something with a very predictable risk quotient.  Very similar to insurance, really, except the other way around.  One mortage will either default or not at some % chance, but it's a one off thing - any good statistician will tell you that you don't do statistics on n=1.  One hundred mortgages, each with some risk level, will very consistently return a particular amount, within a certain error, and thus you have something that people are willing to pay money on the market for. The Greek Piraeus Bank offers such services for trading stocks in Athens Stock Exchange (ASE) and in addition 26 other markets including NASDAQ, NYSE and largest European ones (full list, in Greek). Same goes for Eurobank with a list of 17 international markets and the ability to trade bonds. BETA Securities has also an online platform, but I think it's only for ASE. Some other banks (like National Bank of Greece) do have similar online services, but are usually restricted to ASE. Brokers have the right to charge interest on any stock that they lend you. Since you borrowed the TSLA to short it, the owner of those shares can charge you interest until you return them. If you are not getting charged interest on some shares that you have borrowed to short, consider it generosity on the part of the lender. "It's viable for you,  but the ""investor"" is either stupid or willing and able to write off the investment as a gift for a friend in need, knowing it will probably end the friendship.  The banks make their money off of indebtedness, with the highest returns being on the highest risk loans . If the bank isn't willing to give you that debt on your own,  it's because they already know it's a bad debt. In this case,  trust the banks. If you can't come up with the downpayment on your own, you won't be able to meet your other commitments on this contract." "Yes... but it is a matter of balancing risks.  It is wiser to keep a small amount of ""ready cash"" as an emergency/buffer -- and to suffer the gradual loss to inflation...  Than it is risk becoming ""stuck"" in an emergency with zero dollars in any (low or no cost) source of funds -- those kinds of ""emergencies"" ($500 or $1,000 ""unexpected/unbudgeted"" expenses) are fairly frequent and virtually inevitable.  You lose vastly MORE money when you are forced to borrow those amounts (interest -- even **low-rate** loans -- is virtually always higher than the average inflation rate)."