TSC 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 solid outperformance on a total return basis.The following ratings changes were generated on Monday, April 13. We've upgraded Apple ( AAPL) from hold to buy, driven by its increase in net income, revenue growth, largely solid financial position with reasonable debt levels by most measures, expanding profit margins and good cash flow from operations. We feel these strengths outweigh the fact that the company has had lackluster performance in the stock itself. Net income increased 1.5% compared with the same quarter last year to $1.6 million. Revenue increased by 5.8%, and earnings per share also improved. Apple has no debt to speak of and a quick ratio or 2, demonstrating its ability to cover short-term liquidity needs. Its 36.3% gross profit margin is strong, having increased from the year-ago quarter, and its net profit margin of 15.8% is above the industry average. Net operating cash flow increased 41.3% to $3.9 billion compared with the year-ago quarter. We've upgraded Enterprise Products Partners ( EPD) from hold to buy, driven by its compelling growth in net income, notable return on equity and impressive record of earnings per share growth. We feel these strengths outweigh the fact that the company has had generally poor debt management on most measures that we evaluated. Net income increased by 40.9% compared with the same quarter a year ago, from $161.9 million to $228.1 million. Return on equity also rose, a clear sign of strength within the company. EPS are up 46.7% in the most recent quarter compared with the year-ago quarter, though we anticipate underperformance in the coming year relative to the company's two-year pattern of EPS growth. Revenue fell 32.3% compared with the prior-year quarter. EPP's gross profit margin is 14.3%, though it has managed to increased since the same period last year. Its net profit margin of 6.4% compared favorably with the industry average.