I think one of the greatest one day non-IPO debut runs ever, without the real possibility of being stopped out, had to have been achieved by Yahoo. Early morning it was announced Yahoo was going into the S&P. It was a first for this kind of stock. Yahoo literally was bought all day long. I think it was a 20 point+ gain. Within a week the stock had gone from $270ish to $350ish.
Who could ever forget Rambus. Within three weeks, the stock went from $70ish range to $450++++++++++++
How about Commerce One putting on one of the most amazing pre-split runs. $280ish range to over $525++++
Than there was ICGE. What a run. It ran up nearly 60% in a week pre-split & than post split pulled another double as it broke the $100 mark within three days. Amazing.
Best IPO debut had to have been Juniper. Not a heck allot of downside from the opening day & second day. THe range was $90ish to an opening of $100ish. Within a week this bad boy was in the $150 range and went on a huge run. Had a 2-1 split breaking $250 mark. Within a few months, back over $300ish and announced a 3-1 split. THat summer again running over $220ish with yet ANOTHER 2-1 split.
GNET had to have been one of the traders favorite. This thing was discovered in late winter 1999. Went from like the $5ish range over to $100 bucks in a week. Two whopping stock splits 6 months later and the thing was still running hard.
Worst IPO debut was PALM. Bidders hand slapped themselves all the way up to $130ish and than PALM opened and fell flat on its face. Within a week tanking to the $70ish range. Related to this, COMS put on a HUGE HUGE run b4 the spin off of PALM.
Another notable run was Oracle in the fall 1999. It basically doubled in less than three months. FOr a stock with such a huge float that was a pretty big deal. Remember, all of those wonder IPO's debuted with ridiculously small floats. It did not take that much to make these suckers move.