UBS senior bank analyst Brennan Hawken said it's a good time to buy financials, according to an interview with CNBC. Among others, Hawken has Buy ratings on Goldman Sachs Group Inc , Morgan Stanley , Citigroup Inc and Bank of America Corp . UBS said it became more constructive on banking stocks about a month ago, shortly before JPMorgan Chase & Co. CEO Jamie Dimon bought millions of dollars worth of his company's stock.