After more drama than most new offerings, Groupon (Nasdaq: GRPN) finally went public on Friday.

The daily-deals leader priced its IPO at $20 a share -- ahead of its initial $16 to $18 pricing range -- but it wasn't enough. The stock popped higher at the open, and now you can expect head-shaking cynics to have a field day with Groupon's lofty valuation and questionable moat.

It's hard to blame them. With a whopping 632.8 million shares outstanding, Groupon opened at $28 to give it a market cap of nearly $18 billion. Groupon is still a young company, sacrificing near-term profitability for the sake of territorial growth. It will be a volatile stock until the market gets a clearer picture of what the flash-sale giant is truly worth, and that represents an opportunity for both bears and bulls.

Now, if I had a nickel for every joke I heard about Groupon being so expensive that the IPO could use a Groupon offer, I'd be as rich as the company itself.

Briefly in the news
And now let's take a quick look at some of the other stories that shaped our week.

  • Take-Two Interactive (Nasdaq: TTWO) finally released a smoking-hot trailer for its upcoming Grand Theft Auto V video game, but it has yet to set a release date.
  • Sirius XM Radio (Nasdaq: SIRI) added fewer net subscribers than expected in its latest quarter, and revenue growth of 6% isn't very scintillating, but earnings and free cash flow are climbing a lot faster.
  • Patio-deck giant Trex (NYSE: TREX) posted disappointing quarterly results, providing even bleaker guidance for the current quarter. However, Trex did excite investors by projecting "significant" growth in 2012 after checking with its distributors. Hit the deck!
  • Tesla Motors (Nasdaq: TSLA) posted better-than-expected results, and the electric-car maker has seen 6,500 pre-order reservations for next year's more accessible Model S sedan. Talk about charged-up demand for a $50,000 electric car!

Until next week, I remain,

Rick Munarriz

The Motley Fool owns, and Motley Fool newsletter services have recommended buying, shares of Take-Two Interactive Software. Try any of our Foolish newsletter services free for 30 days. We Fools don't all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Longtime Fool contributor Rick Munarriz calls them as he sees them. He owns no shares in any of the stocks in this story and is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Motley Fool has a disclosure policy.