&gt; The wholesaler is required by law to meet or beat the NBBO --- the &quot;exchange price&quot;.<p>Then again, this discussion is on a thread about the US DoJ investigating wholesalers for potentially <i>breaking the law</i> when it comes to what price the required to provide (though apparently a different requirement than the NBBO, specifically, the &quot;best execution reasonably available&quot;.)<p>A legal requirement doesn&#x27;t mean its going to happen in practice, it means that there is, at least in theory, a remedy available if it doesn&#x27;t.<p>(Then again, not meeting or beating the NBBO seems a bit more obvious than not providing the best execution reasonably available, so I&#x27;d be somewhat more surprised if this wasn&#x27;t happening simply because it would seem hard to get away with except in some extreme edge cases.)