Thanks for your inputs.
I thought the working in a IT operation department as a BA in a big bank is stable(according to the hr person; she said that since this job is more about credit data analysis and process (SAS and data process), and other responsiblities that a BA usually has, IB crunch has no negative impact on this position, so it is stable, and you have a phd, people may think that you are very talented, and you are the last one to be laid off, if there is one); the pay may not be as high as that in a big engineering/IT company.
However, I found out that the pay in Toronto financial industry, over all, is not high, not as high as expected. Look at those nice high-rise buildings; they make people like me think that people working in those buildings must be richer than other industry...maybe they put too much money on those buildings/facilities, and pay too much to senior management, ceo, cfo, md, and so on. The intermediate level or below cannot get a fat paycheque without a promotion.