WHOOPS: A Fat Finger Mistake Sent A Stock Shooting Up Over $300 In Less Than A Second This Morning

This morning Nanex, a Chicago-based market research firm, pointed out that Kemper Corporation's stock surged $318.89 at 9:36:44 a.m., and for a brief moment, it added $18 billion to the company's market capitalization.

Check out the chart below:

Naturally, this kind of thing doesn't happen every day, so we decided to look into it.

According to a source close to the situation, the stock trades on the NYSE, but these particular trades were executed on the NASDAQ because there was more liquidity on that exchange. It seems like someone submitted the wrong number and that's why this all went down.

So no, this was not a buggy high frequency trading algorithm, it was an infamous "fat finger" mistake.

The trades were later canceled (labeled "busted" trades) by NYSE:

11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|43160|95|39.01000|300|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|43161|66|39.01000|300|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|43162|95|39.01000|200|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455079|66|39.01000|200|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|43163|95|45.45000|1900|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455082|66|45.45000|1900|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|43164|95|357.90000|100|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455085|66|357.90000|100|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455088|66|357.90000|3|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455090|66|357.90000|3|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455092|66|357.90000|3|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455094|66|357.90000|6|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455096|66|357.90000|2|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455098|66|357.90000|4|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455102|66|357.90000|2|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455105|66|357.90000|1|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455111|66|357.90000|3|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455118|66|357.90000|3|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455123|66|357.90000|1|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455126|66|357.90000|2|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455130|66|357.90000|3|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|43776|95|357.90000|400|||0|||
11:22:49|eKMPR|NYSE|NQEX|Cancel;Busted;|11:22:49|455133|66|357.90000|400|||0|||

But if you check out the stock's moving day range, it still reads from $34.80 - $357.90.

Wild stuff — be careful out there, and watch your decimals.