Do MD call candidates to drop them?

Usually they only call when you get the job. I suppose in certain places or circumstances they might call to let you know you were not picked, but that is the exception not the rule.

Agree. Only exception that I can think about is if you have had a very strong relationship with this particular MD prior to interviews. Otherwise, probably not wasting their time...

they may be the decision maker and wants to just check you out prior to HR giving you a call later in the day with an offer.. that type of thing.

An MD once called me to essentially let me know I was put "on hold" after a final round. I would say I probably had a better rapport with him than anyone else throughout the interview process though.

Same as above. MD called several times to put me on and keep me on hold. He was the only guy from the bank that contacted me after second rounds. Didn't make much sense because I'd only met him once and had better relationships with other people at firm.

the MD emailed to say he will call me by end of last week.. but did not do so... whats next?