We had a pretty funny and ironic contrast Thursday between two companies that used to be paragons of growth: Research In Motion (RIMM) and Nike (NKE).

We all know that Research In Motion rallied mightily and Nike fell hard. But it wasn't revenue growth, which is usually the focus of growth investors, that determined the trajectories.

It was margins.

You see, it is dawning on people now, including me, that the RIM restructuring is working and that the company has managed to cut costs so aggressively that it is actually building both cash flow and cash. That's a major turn. If it can put out a new version of Blackberry, maintain its subscriber growth and continue to stay important with the enterprise, then it will not be able to stay independent for long. It will be snapped up. Things no longer seem terminal at RIM, even as it is barely growing.

So what? This is a $4 billion profitable company with terrific patents and an 80 million-user installed base. It's no longer a short. It might even be a long.

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But Nike? I like it. The trust owns it but was trimming it into the quarter. Why? Because the company is not making enough off of its sales. Unlike with RIM, the gross margins are contracting, and even though the cash is building and revenue, particularly in North America, was fabulous, you can't be thrilled when the big sales can't be brought down to the bottom line.

Even though North American sales grew 23%, even as emerging-market sales gained 22%, the 80-basis-point decline in gross margins spooked people, as did the subpar 6% sales growth in China.

We keep hearing that all people want in this market is good sales growth. Nike had it, and no one cares. Research In Motion doesn't, and people are thrilled.

But then again, RIM can be taken over and Nike can't.

And that's the real story.

Jim Cramer is a co-founder of TheStreet and contributes daily market commentary to the financial news network's sites. Follow his trades for Action Alerts PLUS, which Cramer co-manages as a charitable trust and is long NKE.

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