This paper provides evidence on market surveillance from stock exchanges and securities commissions from 25 jurisdictions in North, Central and South America, Western and Eastern Europe, Africa and Asia. Stock exchanges as SROs engage in a greater range of single-market surveillance of market manipulation than securities commissions, but the scope of cross-market surveillance activity is very similar among stock exchanges and securities commissions. Cross-market surveillance is more effective with information sharing arrangements, and securities commissions are more likely to engage in information sharing than stock exchanges. The scope of cross-market surveillance is highly positively correlated with trading activity, unlike the scope of single-market surveillance. The data also indicate that as at 2005, there is ample scope for jurisdictions to expand their cross-market surveillance and thereby stimulate investor confidence and trading activity.