Rates are about as low now as they’ve ever been. Houses about as cheap as they’ve been since the early 2000s. But sales are as low as they’ve been since the early 90s.

Talking to Realtors, it becomes clear that the weak link in the housing chain is right in the middle: Current homeowners who’d normally be ready to move up and out to bigger, nicer properties, but who find themselves stuck in place as price declines eat away the equity that was supposed to make the dream of a new home possible.

“I’ve been saying to my clients and myself that we are in gridlock,” said Marcia Solberg, an agent with Macdonald & Wood Sotheby’s International Realty in Duxbury. “Outside of that group of people who need to do a short sale or who can’t afford to stay in their house, there’s still a whole group of people who have secure jobs, they have sufficient income, they have sufficient equity – [but] they’re looking at the days on market for a property and they can’t carry two homes for a year.”

A look at the pool of borrowers from five years ago spotlights the issue. We examined data on single-family home sales from 2006 through 2011 provided by The Warren Group, publisher of Banker & Tradesman. Of 50,724 properties purchased in 2006, 2,116 were sold again in 2010, with an average price decline of 12.1 percent.

A further 1,710 properties purchased in 2006 sold again in 2011 – and the price decline widened to 13.2 percent.

Even for sellers who break even on the sale of their former home, a new purchase means coming up with a new down payment from scratch, not to mention thousands of dollars in closing costs.

“Where we are today, is that that move-up buyer, in order to move up, are going to have to have saved a down payment, unless they have a lot of equity in the house or they’ve really improved the property,” said Amy Tierce of Needham-based Fairway Independent Mortgage.

Vicious Circle

The median price of single-family homes purchased in 2006 was $345,000, according to The Warren Group. Through October, the latest month for which data is available, the median price for a single-family home in 2011 stands at $293,000 – a 15 percent drop. The median price represents the point at which exactly 50 percent of homes sold were priced above that point, and 50 percent were priced below it. It is generally used as the indicator for the price of an “average” home in Massachusetts.

But even with the price declines, upgrading still isn’t cheap.

It stands to reason that if a current homeowner who purchased that average home in 2006 were to want to expand or indulge in a nicer lifestyle, they may well bang up against the Federal Housing Administration’s conforming loan limits. In Massachusetts, those limits currently stand at $417,000 for much of the state, and $465,750 for the metro-Boston region. In Nantucket and Dukes Counties, the limit is $625,500.

Loans priced over the limit can’t be bought by Fannie and Freddie; instead purchasers must take out a privately-financed “jumbo” loan. These days, lenders usually require 20 percent down payment to even consider a jumbo, and without equity from the sale of their former home, that’s a tough nut to crack.

In some cases, buyers are willing to wait out the market by renting out their former home while they purchase a new one. But that doesn’t mean their banks are.

Judy Reynolds, broker/owner of Evergreen Realty in Sterling, said she’s had several buyers ready to move forward on a purchase only to discover while the buyer maybe be able to “put 10 percent down [on the new property], ratios on your overall debt become too onerous for somebody to accept,” she explained. “Even if you can make your payments, it doesn’t mean the bank is going to think you’re ready to do that.”

Even for potential sellers in a financial position to move themselves, the slow market and thin inventory can scare them off of listing. Gary Rogers, an agent with RE/MAX On The Charles in Waltham, had a client who already had their eye on their own dream home, but were hesitant to list their current property.

“They just put their house on 30 days ago, and we’ve already adjusted the price once,” he said. “It’s a vicious circle: We probably had 20 people at the open house, and 15 of them had a house to sell that’s not on the market.”