how to disable margin/leverage in backtest?

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how to disable margin/leverage in backtest?

posted Mar 2, 2017

Seeking Help Getting Started

Hi,

I'm seeing some weird things while backtesting. With a test with initial capital of $100K, I see on a few days, $300K or $400K were purchased.
The code has a check:

if context.portfolio.cash > X:  
#buy stock of amount X

Is this not enough to prevent margin from being used?

Thanks!

1 response

I found in a couple of old threads that context.portfolio.cash isn't updated per order() call, but rather per minute.
So, I just added a

temp_cash = context.portfolio.cash

at the beginning of scheduled method.
then manually decrement order value for each order call
temp_cash -= X and check if temp_cash > X instead of context.portfolio.cash > X before ordering more stocks

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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.