An estimated 300,000 consumers that put new-car purchases on hold over the summer may be on their way back to the lots, according to Edmunds.com. 

And approximately one-third of those very same consumers have already returned to the market, the company noted — causing what it calls a “mini-bubble” of new-car sales that the industry has enjoyed the past few months.

That said, dealers should continue to feel the positive effects of high demand into 2012, as Edmunds.com chief economist Lacy Plache predicts another 100,000 consumers that deferred buying a car this summer should hit the market again by March.

“New-car buyers now have much better buying opportunities that just weren’t available this summer when production shortages from the Japanese earthquake limited supply and raised prices,” Plache further explained.

“As a result, this ‘mini-bubble’ should support sales well into the first quarter of 2012,” she added.

But with 200,000 consumers predicted to push industry sales high in the coming months, what is the fate of the remaining 100,000 deferred purchases?

In likely some good news for used-car dealers, Plache noted that some of these deferred buyers may have already turned to the used-car market.

But on the other hand, the used-car market also saw tighter inventories and higher prices this past summer, in part due to increased demand for Japanese and fuel efficient cars by consumers and dealers.

The result: “The ratio of new to used cars sold from May to August actually increased slightly to 0.33, compared to 0.32 for the same period last year,” Edmunds.com analysts explained.

Noting that some of the remaining deferred buyers might also be swayed by the unstable economic environment, Plache surmised, “The exact number of remaining sales that will return — and their exact pace  — depends on economic conditions, since some portion of buyers likely have been deterred by current economic uncertainty.

“But positive trends in the U.S. economy, such as steady job growth, moderate inflation and income growth could reassure buyers enough to push them to finally make their new-car purchases,” she continued.