I just talked with Tim Reilly, managing director and head of North America electronic execution sales at Citi about Citi Electronic Execution 's IS Shadow Strategy. Here is what he had to say:

"The buzz is all about crossing networks and dark pools," Reilly says, "But there's a frustration that you're not certain that orders will get done. This offers more certainty that you'll get the order done and efficiently hit the various major crossing engines as well."

"The child order is out in the market following an Implementation Shortfall strategy while simultaneously the parent is allocated opportunistically across nondisplayed venues and its constantly optimizing," Reilly says, adding that the algorithm hits most major dark pools and also utilizes nondisplayed order types on ECNs.

"I can trade faster in the actual market I if I don't have as big of an order and it won't make as big of an impact when I'm trading," Reilly says. "It's a natural evolution of these rules-based models that are now able to learn from market behavior and dynamically adjust how they actually trade."

For more, read Citi Electronic Execution Crosses Dark Pool Algorithim with Implementation Shortfall.