A few days ago, I asked whether investors should get charged up about the IPO of lithium-ion battery maker A123 Systems (NASDAQ:AONE). Well, the market has spoken -- loudly.

On Thursday, the offering was boosted from 25 million to 27.5 million shares (plus 680,501 shares sold by existing stockholders), and priced at $13.50 per share. Investors piled on all day, pushing the share price up past $21 at one point.

So much for our preliminary share structure calculations. Based on the current price of $19.61, here's an update:

Share Structure and Capitalization

Numbers

Shares outstanding

98.2 million

Market capitalization

$1,925 million

Cash and equivalents

$457.7 million

Debt

$16.2 million

Enterprise value

$1,483.5 million

Book value

$515.1 million

Data from company filings.

Whoa, Nelly! Before the IPO, we were looking at a market cap of barely over $1 billion, and an enterprise value of less than $700 million. Now, A123 is priced at around 3.75 times book value, and its ratio of enterprise value to lifetime total sales has jumped to 7.9. Jeez, A123, leave some hype for Shanda Games (NASDAQ:GAME) and Select Medical (NYSE:SEM), would you?

At around half its current valuation, I was cautiously optimistic that A123 could maybe meet the growth expectations baked into the cake, like Google (NASDAQ:GOOG) did back in the day (despite the disinterest of Fools like Bill Mann at the time). Now, I'm not nearly as sure. I'm going to take the weekend to ponder the growth outlook here, and I suggest anyone long or thinking about going long the stock do the same. That doesn't just mean taking the market size estimates being thrown around for 2015 and 2020 and extrapolating A123's market share from that.

I'll be back next week with my findings. In the meantime, take a moment to tell the rest of us what motivated you to either buy or avoid these shares in their first two days of trading in the comments section below.

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Fool contributor Toby Shute doesn't have a position in any company mentioned. Check out his CAPS profile or follow his articles using Twitter or RSS. The Motley Fool has a disclosure policy.