Why quantopian don't separate long/short stock and sell short/buy to cover.
I am confused with
order(stock,-x) How do i know it's a sell or sell short?
And do i need to check my position first before i sell short every time? to say i have 20 shares. and the algorithm tell me to go short 100 shares, does this process = I sell my 20 and go short another 80, So how to deal with this kind of situation?
Hi Eric,
There are a couple different order methods you can use to explicitly sell your shares. To close out an existing long position you can call either of the following:
order_target_percent(context.aapl, 0)
order_target_value(context.aapl,0)
For more reference, check out this thread: https://www.quantopian.com/posts/sell-vs-short
For your second question, if you do no limit your leverage in the backtest then your algo will allow you to borrow an unlimited amount of money, and you may see unrealistic returns. You can monitor your portfolio cash using the record method to track the behavior. Also, try this logic check to control your leverage:
if current_cash > 0: Also, I wanted to point you to a template created by Brandon and Dan that limits leverage in an algo. It is useful for a long-only strategy: https://www.quantopian.com/posts/template-limiting-leverage-by-brandon-ogle-and-dan-sandberg
Cheers,
Alisa
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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 Quantopian.
In addition, the material offers no opinion with respect to the suitability of any security or specific investment. No information contained herein should be regarded as a suggestion to engage in or refrain from any investment-related course of action as none of Quantopian nor any of its affiliates is undertaking to provide investment advice, act as an adviser to any plan or entity subject to the Employee Retirement Income Security Act of 1974, as amended, individual retirement account or individual retirement annuity, or give advice in a fiduciary capacity with respect to the materials presented herein. If you are an individual retirement or other investor, contact your financial advisor or other fiduciary unrelated to Quantopian about whether any given investment idea, strategy, product or service described herein may be appropriate for your circumstances. All investments involve risk, including loss of principal. Quantopian 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.