  A continuous-path semimartingale market model with wealth processes
discounted by a riskless asset is considered. The numeraire portfolio is the
unique strictly positive wealth process that, when used as a benchmark to
denominate all other wealth, makes all wealth processes local martingales. It
is assumed that the numeraire portfolio exists and that its wealth increases to
infinity as time goes to infinity. Under this setting, an initial enlargement
of the filtration is performed, by including the overall minimum of the
numeraire portfolio. It is established that all nonnegative wealth processes,
when stopped at the time of the overall minimum of the numeraire portfolio,
become local martingales in the enlarged filtration. This implies that
risk-averse insider traders would refrain from investing in the risky assets
before that time. A partial converse to the previous result is also established
in the case of complete markets, showing that the time of the overall minimum
of the numeraire portfolio is in a certain sense unique in rendering
undesirable the act of undertaking risky positions before it. The
aforementioned results shed light to the importance of the numeraire portfolio
as an indicator of overall market performance.
