Do you qualify for a jumbo mortgage?

According to this well-written short piece on the state of the jumbo home loan market in the United States;

To qualify for a jumbo mortgage today, you should expect:

• To make a down payment of at least 20 percent for a purchase (or have at least 20 percent equity in a refinance).
• To document your income.
• To get an adjustable-rate loan, because fixed-rate jumbos are relatively rare.
• For your monthly mortgage payment to be no more than 38 percent of your income before taxes.