The New York Stock Exchange (NYSE) has been using Python since 1998. This email from Thanos Vassilakis, then a programmer for NYSE, highlights the reliability, manageability, and ease of use enjoyed by Python programmers (not to mention family life!):
On the New York Stock Exchange we use three languages in production to deliver serious trading services to the Specialists: c, C++, Python.
Perl, tcl/tk, Java are used but for scripting, tools, and minor services where performance and memory foot print are not an issue. Yes, used correctly Python meets our performance, security and reliability requirements.
We have had Java projects and launched Java services, they have all failed. We have many in the pipeline (thanks Big Blue) but NYSE's only serious internet based service is written in Python, and was launched in 1998. It is still up in it's sixth version, with no down time! The fifth version was rewritten in Java, 6 months overdue, failed, and replaced by python ( which took two weeks).
Here at SIAC and NYSE Python is recognized by management to give results that other languages just can't achieve.
For performance we have extended Python with our own specialized c objects, and we have used swig extensively to integrate to our legacy code, and middleware.
Thanks Python, you let me get home to my kids.
NYSE has run Python since 1998, when it rolled out its first internet application. It has experienced no downtime and has enjoyed Python's significant backward-compatability character ever since.