Knight's share of trading in Apple Inc shares bounced back to 19.4 percent in late morning trading, roughly in line with the daily average of 20 percent this year to last Tuesday.

Just 1 percent of Apple's volume went through Knight last Wednesday after a software glitch triggered unintended trades in dozens of issues at the open, forcing the market maker to ask its clients to redirect their orders and leaving Knight with a massive loss.

Volume also came back in the Nasdaq 100 tracking exchange-traded fund, to about 9.2 percent of the total. The daily average this year to Tuesday was 13.3 percent, and last Wednesday's volume share at Knight fell to 2.3 percent.

However, some of the highest daily volume issues were still trailing their average by wide margins.

Knight accounted for roughly 2 percent of trading on the SPDR Select Sector Financial ETF on Monday morning, down from a daily average to July 31 of 13.8 percent, Thomson Reuters AutEx data showed.

(Reporting by Rodrigo Campos; Editing by Padraic Cassidy)