CGoering@nyiso.com writes to the NYISO_TECH_EXCHANGE Discussion List:

The NYISO is reserving hours beginning 00:00-01:00, 03:00-04:00, 07:00, 09:00,
11:00-14:00, 18:00, and 23:00 in the April 26, 2001 Real-Time Market as well 
as
the following hours per ECA20001006B to verify prices:

PJM: none
HQ:  05:00
OH:  none
NE:  none

Prices in the April 27, 2001 Day-Ahead Market are correct.

This e-mail information is a copy of the official posting which can be found 
at
the following address on our website:
http://mis.nyiso.com/public/htm/OperMessages/CurrentOperMessages.htm#mm