The move, the first downgrade for the firm from the broker, was made due to concerns over the sales outlook, and the rating was cut to 'neutral' from 'outperform'.
The share price target was repeated at C$65 - which is still higher than the current price of around 60 cents - down 1.3% on the day.
The firm is on track to fall eight days in a row, with shares falling 5.6% over the last seven sessions.
Same-store-sales growth is currently expected to rise to 5% for the third quarter, which ends this month, and then to 5.2% for the fourth quarter, according to analysts.
That compared to 3% growth in the second quarter.
Starbucks is scheduled to report third-quarter results after the bell closes in New York on July 27.