Show HN: A simple way to get options prices for free

Another good source for option prices is: https://datashop.cboe.com

I would not recommend to use the Yahoo or Google apis to get option prices. Some of the bid/ask prices are completly wrong and some expiration dates are missing. I created an option scanner as a side project and found about this bad data quality the hard way.

How's the data quality of OptionWorks? Do they have the indicies? I bought several years of EOD data for SPX from https://www.historicaloptiondata.com/ and found it to be of only moderate quality. (Charting some of the data on multiple dimensions makes the stuff that is padded stick out like a sore thumb... I ended up tossing about 20% of the data).

etrade also has a free API if you have an account: https://us.etrade.com/ctnt/dev-portal

> Is option prices what I think of when I think "Stock Data"?

You may be thinking of simply stock prices or stock fundamentals (income, expenditures, that kind of stuff) but you may also be thinking of other things like sentiment or analyst opinions. There's a huge range of things you can look at. Options prices are certainly one kind of stock data though, they give valuable information like implied volatility (how much the market at a particular time expects the stock to move in a particular period in the then future).

If you're interested in stock data, Quandl (http://quandl.com) has a broad selection of the different kinds available (though you don't have to purchase there) and Quantopian (https://quantopian.com/) has some examples of how to use it.

To be clear though, options are not stocks.

A stock is a share of ownership of a company. You buy it, you sell it, that's it.

An option is a contract between you and another party that gives you the right but not the obligation to buy or sell a stock at a particular price for a certain amount of time.

Practical examples:

- I buy 10 AAPL stock at $100. I now own $1000 worth of Apple. AAPL's stock price rises to $110. I now own $1100 of AAPL stock, which I can sell and make $100.

- I buy a contract that gives me the right to purchase AAPL (an AAPL call option) for $100 (the "strike price" is $100) which expires in 30 days. This right is limited to 100 AAPL shares and I pay $500 for it. For the next 30 days, regardless the price of AAPL stock, I can buy 100 AAPL for $100 each. If the price of AAPL drops, I lose the $500 I paid for the rights. If the price of AAPL rises to the $110 from earlier, I can either buy 100 shares of AAPL for $100 and sell them immediately for $110, making $1000 - $500 (for the contract) = $500, or I can simply sell the rights to someone else and make the profit more cleanly.

This isn't meant to be an exhaustive course on how each security works, just an illustration of exactly how different they are, yet affect each other.

I believe you would like this github.com project.

https://github.com/eliangcs/pystock-data

Edit: I just noticed the owner has decided to stop maintaining the repo just a few days ago. But you can reproduce it using the tools they used.

An option is a contract that sets a price that you can either buy or sell a certain stock for at a subsequent time.

They have a certain value, and therefore prices, but are different from actually owning the underlying stock.

no options are contracts involving stocks

quantmod can pull in stock data easily if you just want to mess around: http://www.quantmod.com/examples/intro/

RStudio + quantmod is a good playground

I've seen this too but I don't think it's particularly valuable as it seems to base the prices on measured volatility, while the actual market prices them entirely differently. You can see in his chart at the bottom that the price diverges from real data by a full dollar at points and that's just for SPY, I'd be interested to see how it goes for something like VIX.