Conforming and FHA mortgage rates improved last week on the combination of weaker-than-expected economic data and new anti-banking rhetoric from the White House.

The S&P 500 shed nearly 4 percent in its worst weekly showing since October 2009 as all 10 sectors fell. As the money left stock markets, it made its way to bonds — including the mortgage-backed variety.

As a result, California mortgage rates fell for the third straight week.

Since shedding 300 basis points in December, mortgage bond pricing has recovered a bit more than half of those losses.  It’s helping with home affordability and opening new refinance opportunities in Santa Rosa and around the country.

This week, though, mortgage rates could rise back up.  There’s a lot going on.

First, on Monday, the December Existing Homes Sales report will be released.  The report is expected to be extremely weak as compared to November.  This is because of a combination of factors including:

1. The initial tax credit expiration date of November 30, 2009
2. Sharply rising mortgage rates throughout the month of December
3. A general slowdown from the holidays and from the weather

Therefore, don’t be surprised by the newspaper headlines you see Tuesday morning.

Other data this week includes the Case-Shiller Index – a measure of home prices nationwide — and the New Home Sales report. The Case-Shiller Index has registered mild home price improvement over the past 8 months and its latest report is expected to show the same.  New Home Sales should be similarly strong.

But, the biggest news of the week is the first Federal Open Market Committee meeting of 2010. 

The Fed meets Tuesday and Wednesday this week and Wall Street will be watching closely.  The Fed is not expected to change the Fed Funds Rate from its current target range of 0.000-0.250 percent, so, instead, markets will watching for the Fed’s post-meeting press release.

What the Fed says about the economy will be much more important that what it specifically does about the economy for now.  If the Fed says the economy is growing as expected, look for mortgage rates to rise. Conversely, if the Fed says the economy is at risk, expect mortgage rates to fall.

The safest rate lock strategy this week is to lock your mortgage rate before the Fed’s 2:15 PM ET adjournment Wednesday.  Rates will be bouncy all week, but once the Fed’s press release hits the wires, it’s anyone’s guess what will happen.