Share New Research 
For stocks there is the number of outstanding shares which, in conjunction with share price, shows the market cap of a stock (e.g. Stock XYZ has 1MM shares outstanding at $100 each, giving XYZ a $100MM market cap). Is there an equivalent view of shares outstanding for stock options? E.g. Company XYZ Call options of $110 Expiring on 12/7/18, there are 50k options outstanding (aka 50k of these options have been purchased).
I keep reading in various places that there is a lot of Short sell interest of stocks like Tesla, and various figures thrown around of how many $billions short sellers are set to lose if the stock price increases (aka doesn't drop to the put mark), but I haven't discovered what data is used to make these calculations.
Many thanks
ChainsawDR
SLPAdvisory
Jing Wu
Unlike stock trading, in which there is a fixed number of shares outstanding, Options whether issued or not are a right to buy shares. Options trading can involve the creation of a new option contract when a trade is placed in my view.
Open interest is the total number of option contracts that are currently open – contracts that have been traded but not yet liquidated by either an offsetting trade or an exercise or assignment. It might be a useful measure but it's hard to know whether the options are bought or sold from the open interest.
OpenInterest is a property of option contract. You can retrieve the OI data with contract.OpenInterest.
ChainsawDR
Thank you both for your help
Ernest Shaggleford
One free source for high short interest. TSLA is currently 26%.
http://highshortinterest.com/all/
ChainsawDR
The material on this website is provided for informational purposes only and does not constitute an offer to sell, a solicitation to buy, or a recommendation or endorsement for any security or strategy, nor does it constitute an offer to provide investment advisory services by QuantConnect. In addition, the material offers no opinion with respect to the suitability of any security or specific investment. QuantConnect makes no guarantees as to the accuracy or completeness of the views expressed in the website. The views are subject to change, and may have become unreliable for various reasons, including changes in market conditions or economic circumstances. All investments involve risk, including loss of principal. You should consult with an investment professional before making any investment decisions.
To unlock posting to the community forums please complete at least 30% of Boot Camp.
You can continue your Boot Camp training progress from the terminal. We hope to see you in the community soon!