Overview, with further links: <a href="http://www.sec.gov/answers/dfnctco.htm" rel="nofollow" target="_blank">http://www.sec.gov/answers/dfnctco.htm</a> [edit] according to the regs here <a href="http://www.law.uc.edu/CCL/34Act/sec12.html" rel="nofollow" target="_blank">http://www.law.uc.edu/CCL/34Act/sec12.html</a> ...it's pretty open-ended, ie, no timeframe mentioned, as I read it.