In one of the busiest weeks for new issues, a whopping seven companies went public last week.

With the Dow and S&P 500 near record highs, the mad scramble to go public makes sense. Companies hoping to raise money through IPOs want to hit the market at a time when investors are hungry for equities.

If the appetite isn't there, underwriters will struggle to price new issues at valuations that are acceptable to the prospective newbies. IPOs and bull rallies go together like chocolate and peanut butter.

There's never really a perfect climate for all debutantes.

Four of last week's IPOs served up double-digit percentage gains from their offering prices, but two of the other three closed out their first week on the market in the red.

Let's take a look at last week's rookie class:



March 22


Five Oaks Investment




Marin Software




West Corp.








Enanta Pharmaceuticals




Model N








Source: The Wall Street Journal.

Here's a closer look at the five best performers.

Marin Software (NYSE: MRIN) is a digital marketing manager, allowing companies to manage their digital advertising strategies across search, display, mobile, and social media platforms. Marin has yet to turn a profit, but revenue soared 65% to $59.6 million last year. As advertisers turn to online solutions to get heard more effectively than through traditional media outlets, Marin's positioned well to keep growing.

At a time when the market's hungry for income in this low-yielding environment, REITs -- or real estate investment trusts -- have been populating the exchanges. REITs pass on the vast majority of their funds from operations to investors. Aviv REIT (NYSE: AVIV) isn't your garden-variety trust that snaps up residential or commercial real estate, and that's actually a good thing. Investors have largely stayed away from traditional mortgage-based REITs, and that includes ignoring Friday's debut of Five Oaks Investment. Aviv, on the other hand, owns 258 nursing homes that it then leases out to seasoned operators.

Enanta (NASDAQ:ENTA) is a biotech working on hepatitis C treatments. Enanta is partnered with more-proven drug partners on its treatments that are in various stages of the long regulatory approval process. Enanta had to settle for pricing at the low end of its initial range, but retail investors gobbled up the biotech last week.

Model N (NYSE:MODN) doesn't make cars. It's in the hotter niche of enterprise software, providing revenue management solutions for the medical and high-tech industries. Model N was one of last week's biggest winners -- up 19% from its starting line of $15.50 -- and it popped another 8% yesterday.

Finally, we have Tetraphase (NASDAQ:TTPH)Not every young biotech is the same, and investors saw the divergence when Tetraphase hit the market a day before Enanta. As Enanta shares have soared, Tetraphase has hovered near its $7 offer price. Tetraphase's lead candidate is a synthetic tetracycline derivative that's seeking approval as an intravenous and oral antibiotic for the treatment of multi-drug-resistant infections.