This reduction in the rate was anticipated since it was felt that the adjustment made by the big banks after the 10 year bond rates fell in January was not enough. Expect the other big banks to follow.
Noted that on the Bank of Montreal website, the rate is advertised as "For a Limited Time Only". Surely these rates will sustain over the peak real estate buying period of April through June, so I think they are just hedging their bets or trying to get the borrowing in early.
I have posted the current best rates from The Mortgage Centre. These best rates are from January 30, 2015. The posted best 5 year fixed rate at that time was already 2.79% (not through a big bank). It illustrates why you might get a better mortgage offer if you use a Mortgage Broker, rather than going to your traditional source of lending. It's very competitive out there! Get a quote from two brokers if you can.
Happy St. Patrick's Day...