I just posted criteria for futures algos which should give you a sense of what we're looking for.
I can tell you that Sharpe will matter as well as beta. In the finance space, when someone refers to 'beta', they are typically referencing the correlation of a particular return stream to the S&P 500 index as you mentioned. But you can also think of beta in terms of any common risk factor. How much is the strategy correlated to the Fama-French factors? To a standard momentum signal? etc.
In general, we're looking for strategies that are uncorrelated to common risk factors. The S&P 500 is just a single example of that. We are working on a risk model to help you determine whether or not your strategy is generating returns because of a common risk factor. This is going to be true for futures algorithms as well.
One of the reasons we aren't looking for strategies with high beta is because investors are not interested in buying something that they can already get at a much cheaper rate (e.g. SPY ETF for S&P 500). Again, the risk model that we are building will help provide some insight into your algo's exposures.
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