Some experts say the mansion market is immune to the real estate meltdown.

Analysts at JPMorgan Chase beg to differ.

A study produced by the bank’s mortgage-bond analysts, including John Sim and Matthew Jozoff, says that the market for expensive homes is in even worse shape than that for inexpensive ones.

For example, the supply of unsold homes in California priced at $750,000 to $1 million has stayed steady, while the inventory of more expensive houses rose.

Tighter lending standards and the lack of cheap financing for these borrowers continue to be key issues, the report says, referring to jumbo mortgages.

In addition, none of the Obama administration’s programs to assist homeowners directly focused on helping the sales of these so-called millionaire homes, the analysts write.

Currently, we have national home prices bottoming in 2011, they explain.

However, prices for more expensive homes may not bottom out until 2012, and ultimately result in peak-to-trough declines in excess of 60 percent (compared to 40 percent nationally).

In an interview with Bloomberg, Sim says, “California is probably worse than other states, but higher-priced homes in general are going to be a problem.”

They’re clearly a problem in Palm Beach, Fla.

The median price of single-family homes sold on the wealthy island in October through December of last year dropped 20 percent from a year earlier, to $2.7 million, according to a Palm Beach Post analysis of data compiled by local attorney Les Evans.