TAS/EDE relative values and one bot share, page-41

The beauty is that if you do it right then there is NO downside. If you only do one side of the trade and just hope to do the other then you may get caught out buying and not be able to sell the other. You make sure you can do both trades if you want to completely eliminate risk. I do add risk by assuming that I will be able to do the second trade within a reasonable time, usually by buying first so that I am not out of the holding.

The other advantage of trades being made within the T+2 is that you don't need any cash to add to the equation. If you don't that would add risk that you may have to sell at a loss.