Global clocks aren&#x27;t required, as batch intervals on different exchanges don&#x27;t need to be synchronized. Although the batch interval is a window of cross-exchange risk, the uniform-price clearing means it is still more efficient (in &quot;volume-space&quot;). Continuous auctions have really short risk windows (more efficient in &quot;time-space&quot;), but the discriminatory pay-as-bid price clearing means that all that risk is shouldered by everyone but the fastest traders (who are thus able to extract arbitrage rents from the slower traders).