Holy cow, I wrote a book!
Last year, one of my colleagues noticed that one particular
which normally trades in the mid- to upper-$20 range,
showed one day of extremely
very similar to the last example
in this series of funny screenshots.
Closer inspection revealed that there was an order to buy
28 shares at $100,000.
Obviously, somebody got the "number of shares"
and "bid price" fields backwards
and ended up losing over two million dollars for the error.
If this were an NYSE stock, this error would have been caught
because trades on the New York Stock Exchange are still executed
by human beings on a trading floor,
so somebody would have said,
"Wait, the two fields are clearly in reverse order"
and fixed the error or at least double-checked with the buyer
before executing it.
(At least I hope so.
Maybe the people on the floor don't care.)
But nope, this is NASDAQ, and some lucky market maker walked off
with over two million dollars.
Maybe the unlucky trader's software will now display a warning
if the price entered is more than, say, twice the current market price.
(With appropriate exceptions for penny stocks.)
In response to the unusual price activity, another colleage chimed in,
"Rats! This always happens to me. I had a limit order at $100,001."