But apparently it wasn't for TD Securities. The investment banking arm of Toronto Dominion Bank might have reasonably thought that its position in the top three underwriters of Canadian corporate bonds was a result of its status as one of the biggest banks in Canada. So although it had a few problems, including regulatory fines, it might have thought it could weather the loss of key personnel like Jason Cope, Sameer Rehman and David Gourlay. Not so much. For the current fiscal year, TD has dropped out of the podium places to fifth position, with market share of just 14%. It's lost ground in public sector bonds as well. Now the bank, which "remains fully committed to this market" is left trying to make "key hires in the broader Canadian fixed income business" to try to get its franchise back. Although nobody is truly irreplaceable, there are always some people who actually do generate as much revenue personally as they say they do. Meanwhile …