While a lot of coverage is often reserved for behemoth blue chips or high-flying small caps, it would be foolish to ignore mid-cap stocks altogether. One company in particular that has begun to raise the eyebrows of mid-cap-savvy investors is Wellcare Health Plans (NYSE:WCG). The company provides managed-care services to government-sponsored health-care programs in numerous states. As a managed-care provider, Wellcare contracts with health-care providers to deliver health-care services to its members. The company has recently seen its memberships rise at a scorching pace.

Last month, the company announced its overall membership had more than doubled -- from 808,000 in the second quarter of 2005 to 2,011,000 by the end of the same quarter in 2006. President and Chief Executive Officer Todd S. Farha stated, "We are pleased with our transformation into a leading national government health-care company. Our operating discipline and focus on execution continue to drive our strong growth."

This growth in membership is attributable primarily to two factors. One is the company's successful launch of new health plans in Georgia, which accounted for more than 275,000 new members. The other key factor behind Wellcare's increase in membership is the growth of its prescription drug plan (PDP) business. The company began offering its plan on a nationwide basis at the beginning of the year, and it has been met with great success. PDP membership grew to more than 900,000 during the second quarter.

The company wields a forward P/E of 16.9, which is comparable to the 12.2 and 15.1 forward P/Es of health-care providers Aetna (NYSE:AET) and UnitedHealth Group (NYSE:UNH), respectively. At a market capitalization of only $2.3 billion, the more agile Wellcare has seen its stock price fare much better than those of Aetna or UnitedHealth over the past 52 weeks. Its price has risen 55% over the past 12 months, while Aetna and UnitedHealth are both down over that same period.

Recent press coverage has noted that Wellcare was not selected for a new contract to provide managed-care benefits to Indiana Medicaid recipients in 2007 after its current contract expires at the end of the year. While this decision might not be news the company was seeking, the loss will basically hamper its operations about as much as the Denver Broncos' running game suffers each time the team loses one of its thousand-yard rushers. It's a non-issue. The company stated in its 10-K that it believes the development will have no material impact on full-year earnings for 2006. Given the growth of the company's business, there is probably little concern for 2007 and beyond. Additionally, the 74,000 members privy to this contract account for only 3.7% of Wellcare's total membership.

On Monday, the company reaffirmed its full-year 2006 earnings guidance, stating its earnings per share would come in between $2.85 and $2.90. This range reflects last month's upward revision from its previous guidance of $2.52 to $2.57 per share. At the time of the revision, the company also reported a lights-out 57% increase in earnings, with second-quarter net earnings of $22.2 million, or $0.55 per share, for the quarter ending June 30, vs. $14.2 million, or $0.36 per share, in the second quarter of 2005.

Wellcare's memberships and earnings are on the rise, and Fools might want to consider this stellar mid cap to supplement a portfolio lacking mid-cap securities. There are some inherent risks in the industry for Fools to take into account before buying, including the unpredictability of incidences of illness or disease, and the notion that medical cost trends are potentially more volatile than other segments of the economy. Additionally, as with any managed-care provider, there is always the possibility for cancellation or suspension of state or federal contracts, and there are substantial barriers to entry with respect to challenges faced in securing Medicaid and Medicare contracts in new markets. Relying on its past experience in the business, Wellcare has done a formidable job of mitigating these risks thus far. As a result, its stock has been a monster since its IPO in mid-2004 and there appears to be little hope of containing it.

UnitedHealth Group is a Stock Advisor and Inside Value selection. Try these or any of the Fool's newsletters free for 30 days.

Fool contributor Billy Fisher does not own shares of any company mentioned. The Fool's disclosure policy is in the best of health.