On March 20, 2017 we experienced a technology issue on NYSE Arca Equities that prevented the exchange from publishing Official Closing Prices in some securities immediately following the market close. I am contacting you personally to emphasize that we take these matters very seriously. I also want to provide you with detailed information on what occurred.

The root cause of the problem has been identified as a software issue that, despite rigorous testing by NYSE and market participants, was introduced in the latest version of software which went live on Monday. NYSE Arca has reverted to the prior version of software. This new software version was developed in anticipation of launching more efficient customer connections to our markets and adding other enhancements for the benefit of customers.

Just after 4 p.m. ET yesterday, it became clear that not all securities had published an Official Closing Price and a small subset of these securities had not conducted a closing auction. Pursuant to our rules, we suspended trading in all securities at approximately 4:13 p.m. ET and cancelled all open orders to reduce risk exposure of market participants. Further investigation indicated that 341 symbols did not successfully complete a closing auction.

Because the Exchange’s Official Closing Prices serve an important function in the industry, we previously adopted rules and methodology to determine the Official Closing Prices if the Exchange is unable to conduct a closing transaction in one or more listed securities due to a technical issue. We invoked that mechanism yesterday. The Official Closing Prices for NYSE Arca-listed securities were determined and subsequently transmitted to the SIP.

For NYSE Arca members with claims for compensation, please notify us in writing by the market open this morning of your intention to seek compensation even if you do not yet have full details.

We take our role as market operator very seriously, and we are working tirelessly to ensure that NYSE Arca Equities offers the performance expected by our customers and issuers. My team and I are, as always, available to speak with you to address any questions or concerns.

Please email us at [email protected] with any questions.

Sincerely,

Stacey Cunningham
Chief Operating Officer
New York Stock Exchange