Today was a good lesson on the benefits of diversification. Even though Frontier Airlines (FRNT) got slammed due to a downgrade from Goldman Sachs, our Buy List not only closed higher, but edged out the S&P 500.

For the record, Frontier fell 7.3% to $7.91 a share. The S&P 500 gained 0.28% and our Buy List rose 0.39%. Not a bad day. We were helped by strong gains from Zimmer Holdings (ZMH), Progressive (PGR) and Commerce Bancorp (CBH).

Commerce rose despite issuing an earnings warning. What caused the stock to climb?

Perhaps the stock rose due to Jim Cramer’s article “Let the Bears Raid Commerce Bancorp." I don’t have access to Cramer’s article, but here’s the free blurb:

Seems the big money can't wait for the Fed to finish and is taking up Commerce on its lower guidance. The compression to its net interest margin could have sent it below $30, if people hadn't realized that was in the cards. I still expect a bear raid on Commerce, but now am confident enough to take the other side of it.

And here’s today’s movement in CBH:

I think there’s a good chance that Cramer’s article moved the stock. I don’t have any proof, and I don’t have any complaints either. He’s liked Commerce for a long time. But here’s my problem. This is how Matthew Goldstein at Cramer’s company, TheStreet.com, summarized today’s Commerce news.

In September, the bank warned that analysts had to reduce their earnings estimates for both the third and fourth quarters. When Commerce issued the warning, analysts had been looking for fourth quarter earnings of 49 cents a share.

For next year, the bank says it expects to earn between 40 cents and 42 cents a share in the first quarter. The consensus estimate before the update had the bank earning 44 cents a share.

Investors, however, ignored the bad news. In midday trading Friday, Commerce shares rose 31 cents, or 1%, to $33.34.

In other news, Business Week discovers Expeditors (EXPD). Lastly, two stocks on our Buy List that look especially cheap right now are Fiserv (FISV) and Lincare Holdings (LNCR). Also, I’m just about positive that I’m going to add Bed, Bath and Beyond (BBBY) to the 2006 Buy List. The stock dropped from $44 on Tuesday to $41.99 today.

I hope everyone has a great weekend!