TheStreet.com Ratings provides exclusive stock, ETF and mutual fund ratings and commentary based on award-winning, proprietary tools. Its "safety first" approach to investing aims to reduce risk while seeking total return performance.TheStreet.com's stock-picking model downgraded Bank of New York Mellon ( BK) to "hold." The company provides custody and data-tracking services for financial firms. The numbers: Second-quarter revenue fell 30% to $3.1 billion, but net income increased 33% to $412 million. Earnings per share decreased 12% to 23 cents, hurt by a higher share count. The operating margin expanded from 19% to 43% and the net margin jumped from 7% to 13%. The company has an adequate liquidity position, with $3.7 billion of cash reserves. And a debt-to-equity ratio of 0.8 indicates reasonable leverage. The stock: Bank of New York is down 3% this year, trailing the Dow Jones Industrial Average and the S&P 500 Index. Still, it's up 40% from its March 6 low. The shares are trading at a fair price-to-earnings ratio of 14, but offer a lackluster 1.3% dividend yield. The model upgraded software maker Citrix Systems ( CTXS) to "buy." The numbers: Second-quarter revenue inched up to $393 million as net income rose 23% to $43 million and earnings per share climbed 28% to 23 cents, helped by a lower share count. The operating margin increased from 7% to 11% and the net margin ascended from 9% to 11%. Zero debt, $580 million of cash and a quick ratio of 1.1 indicate a well-managed balance sheet. The stock: Citrix is up 56% this year, outperforming major U.S. indices, but still has upward momentum. The stock trades at an exorbitant price-to-earnings ratio of 45 and doesn't pay dividends. The model downgraded Host Hotels & Resorts ( HST), a real estate investment trust that buys hotels, to "sell."