I don't see how that's risky, and might even be beneficial to the Banker. Assuming an acquiring company is $1.5B and Dragon was getting $400m in stocks, it would have been impossible to offload it immediately at a good price.

OTOH, offloading the Banker's 0.3% is far more easier. In fact, if the overall value of the transaction is higher because it is an all stock deal, the Banker gets a better deal (after immediately selling) than if it were all cash.