Cramer’s Calls: DuPont Fabros Tech, NVE and A123

Two of Monday’s Lightning Round callers asked about stocks that Cramer didn’t know. Ever humble, he took a pass, promising to do more research and return later with a call. On Thursday, he did just that, and gave viewers an update on one of the week’s top IPOs.

Neil from New York asked about DuPont Fabros Technology , which is neither related to DuPont nor the tech sector. This is a real estate investment trust that owns data center properties and leases them out to companies like Google , Microsoft and Facebook.

Cramer’s big problem with DFT was the rough patch it hit in 2008, as trouble with financing forced it to stop paying its dividend. The credit markets have since eased up, allowing the company to push back its debt maturities to 2011, but Cramer wouldn’t recommend the stock until he knew the dividend was safe.

He likes “the fundamental story” here, because tech companies will continue to need data centers, but he’d rather see investors in a commercial REIT like Brandywine , which offers a nice dividend.

Andrew from New York wanted to know if NVE was a buy. Cramer called this small nanotech company, with just a $265 million market cap, a “fascinating” but “extremely speculative” buy, after it took a $3 hit on Thursday.

NVE makes a “patented but unproven” memory-chip technology called MRAM. But the balance sheet is clean, carrying $41 million in cash and no debt. The company has switched from offering largely research-and-development services to selling products of its own, and last quarter sales were up 41% while net income grew 54%.

The stock is cheap, trading at 22 times earnings with a 25% long-term growth rate, Cramer said, but this one is “not for the faint of heart.” NVE is only for those with “a big appetite for risk.” So use limit orders if you do plan to buy it, and only do so in small increments.

Cramer also took the time to check up on A123 Systems , which priced at $13.50 a share, near the low end of his recommended range for the stock. Now AONE is up 50% to $20.29 in the aftermarket, so investors should take some profits. He had said to not pay more than $19, and the stock has passed that mark.

“Don’t be greedy,” Cramer said.

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