Sales of existing homes took an unexpected and rare jump in August, rising 7.7 percent from July.

Realtors say it's the result of delayed sales from the spring market, which they previously characterized as disappointing.

The results were unexpected because the usual indicators no longer apply.

Mortgage applications have been falling steadily, down again over four percent this week, even though interest rates are hovering near record lows. But mortgage volume doesn't tell us much because fewer buyers are using mortgages. 29 percent of home sales in August were all-cash purchases, largely by investors who returned to the market after a brief respite. 22 percent of buyers were investors, up from 18 percent in July.

"Today's data reflects contract signings that took place in May and June, well before much changed in the global economy in Aug, thus today's figure can be seen as old news," notes Peter Boockvar, an analyst at Miller Tabak.

The bump from leftover Spring sales does not appear to have much mojo heading into the Fall, given the dip in consumer confidence and a change in the conforming loan limits that will push some housing markets into the jumbo range next month. Sales contract cancellations also jumped, with 18 percent of Realtors surveyed reporting at least one canceled sale. That's up from 16 percent in July and a norm of around 4 percent.

With distressed properties (foreclosures and short sales) still making up one third of this housing market and investors driving any sales gains, the outlook for price increases, or even price stabilization remains bleak. Prices are still down over 5 percent in August from a year ago and in the West, where sales spiked over 18 percent, prices dropped in line with that, down 13 percent.

"Given the recent sharp falls in equity prices and consumer confidence, there is a real risk that the 7.7 percent m/m rise in existing home sales in August will not be sustained," says Paul Dales of Capital Economics. "Without a significant surge in sales, sustained price gains just aren't possible."

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