Many of the trades that Goldman Sachs erroneously placed through the New York Stock Exchange, the CBOE and Nasdaq have been or are in the process of being canceled by the exchanges.
Each of the exchanges has a set of rules governing when trades will be "busted" or "adjusted" because they are "clearly erroneous." You can read the NYSE rules here and the Nasdaq rules here. The basic gist of the rules is that when trades fall too far outside the prevailing market price, they'll be canceled or have their prices brought into line with the market.
So how often are the exchanges busting and adjusting? This seems an important piece of data to have in evaluating the quality of our markets. After the massive Goldman error and the glitch that crippled Knight Capital, lots of people are wondering whether the increasing complexity of our exchange trading systems is increasing the rate of errant trading.
But, it seems, none of those people work for the exchanges.
A spokesman for the NYSE said that they just don't keep historical data on erroneous trading. I couldn't find any data on the NASDAQ's website detailing the history of erroneous trading and a spokesperson wasn't sure but doubted such information was available. The same goes for the CBOE.
Update: Now the NYSE says this isn't true. Six hours after telling me they didn't keep a history of trading errors, and a few hours after we published this story, the NYSE changed its story. Now it says it has the data about errant trades but doesn't share it with the public.
It seems odd, to say the least, that this kind of information is unavailable. It means that we can't answer some basic questions about the frequency and fairness of trade cancellation.
The fairness question is important. Smaller market players are suspicious that big traders—Wall Street banks and larger hedge funds—are granted cancellations regularly, while others just get ignored. One trader told me he had tried to have trades canceled a few times but never received satisfaction.
"Anyone but Goldman would have just had to eat the loss," another trader said.
These suspicions run directly contrary to the stated policies of the exchanges, which seem very fair. And spokesmen for each of the exchanges insist on the fairness of their process. But that's unlikely to satisfy those who doubt the fairness of the process.
What might satisfy them are actual facts. But those facts are unavailable. In a world in which we have market data about so many aspects of the market, shouldn't someone be watching the error-bust rate?
—By CNBC's John Carney. Follow me on Twitter @Carney