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 6. We've upgraded Advent Software ( ADVS) from hold to buy, driven by its robust revenue growth, impressive record of earnings per share growth, compelling growth in net income, largely solid financial position with reasonable debt levels by most measures and expanding profit margins. We feel these strengths outweigh the fact that the company is trading at a premium valuation based on our review of its current price compared to such things as earnings and book value. Revenue rose by 25.3% since the same quarter a year ago, and EPS improved. The company has demonstrated a pattern of EPS growth over the past year that we think will continue. Net income increased 62.9% compared with the year-ago quarter, from $3.8 million to $6.2 million. Advent's debt-to-equity ratio or 0.1 is below the industry average, implying successful management of debt levels. Its quick ratio of 0.6 displays a potential problem covering short-term cash needs. Advent's gross profit margin of 72.6% is high but has decreased from the same period last year. Its net profit margin of 8.3% is below what it was in the year-ago quarter. We've upgraded Chipotle Mexican Grill ( CMG.B), which engages in the development and operation of fast-casual, fresh Mexican food restaurants, from sell to hold. Strengths include the company's robust revenue growth, largely solid financial position with reasonable debt levels by most measures and notable return on equity. However, we also find weaknesses including a generally disappointing performance in the stock itself and poor profit margins.