Quote from bone:
If one's interest lies in simply capturing a bid/ask spread and avoiding "non-random drift" (??) then a very restrictive pure arbitrage strategy is your only real option.
And you will not find a technically pure arbitrage opportunity in a retail setting - at least, not for long.
And in a bank or HF desk scenario, the returns will almost certainly be too modest to justify the sunk capital costs and financing.
There are plenty of very deep pocket basis traders in the world already.
Regarding the "non-random drift" ( ? ), we actually model for convergence and divergence - it's the cornerstone for our strategy.
Yes & no.
There are a number of pairs out there where one leg has a much wider bid/ask than the other, and yet the pair tracks reasonably well, with some involving multiple legs. The tricky part, for this convergence only strategy, is establishing which pairs are stationary, and trading off the random events / unusual data points -- the outliers in the series. Random data points need to not be an accumulation of trades leading to a non-stationary relationship. If the drift is non-random there is no relationship there.
Not sure this is overly restrictive, but yes, it is conservative & low risk, and may not suit a reatil trader with small capital and no leverage. Yes, in a retail setting, transaction costs are an issue, but there are a lot of DMA providers for small insto customers now, where the costs are acceptable.
In a bank or HF desk scenario, this kind of thing is two pronged. It's both prop, and customer facilitation. Liquidity for clients is created by the bank being willing to take a side of certain flow, giving the customer price improvement. In addition the strategy can, and is applied to various asset classes as well as derivatives. At it's lowest risk, on a derivs market making desk, making near pure hedges [different pricing]. At it's simplest, for rolling over positions toward expiry. At it's riskiest perhaps, to punt on mergers getting through, target vs acquirer.
As for justifying sunk capital costs, most if not all of the global brokers already have reasonably fast DMA platforms now, so the infrastructure is already there. By comparison, this kind of strategy is pretty low cost to setup, and then low risk to run.
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I'd be interested to know more about modelling for divergence rather than convergence.