SAN FRANCISCO -- If ever a man-bites-dog story were to be written, it would be on the day memory-chip maker Micron Technology (MU) - Get Report meets the Street's expectations. On Tuesday, the company reported earnings of 58 cents a share for the second quarter that ended March 2, 16 cents less than the Street had expected.

But longtime watchers of the volatile memory-chip market know that the one thing they can count on is a Micron surprise. Just look back. In the first quarter that ended Dec. 2, Micron lost 7 cents a share; the Street expected an 18-cent loss. In the fourth quarter, it lost 10 cents a share; the Street expected it to break even. In the third quarter, it earned 58 cents a share; the Street expected profits of 74 cents.

What's so hard about calling earnings for this company? Chip pricing. Memory is a commodity product -- all the chips are basically the same -- and the companies that sell them -- Micron,

Hyundai

and

Samsung

-- compete only on price. Prices depend on two things: how many chips the manufacturers pump out of their factories and how many of those are bought.

Supply levels are easy to figure out, says

Warburg Dillon Read

analyst Greg Mischou, whose firm is not an underwriter of Micron. Chip purchasing is a different story. Computer makers like

Dell

(DELL) - Get Report

typically order memory chips at the last minute because they are readily available, while Dell has to order microprocessors in advance, Mischou says.

That means that any dips or surges in computer buying toward the end of a quarter will greatly affect memory pricing and Micron's earnings. So as far as predicting the future, Mischou is sticking to some generalities. The June quarter is usually a lousy one for computer sales and could be bad for Micron, but sales of

Windows 2000

and its consumer version should boost computer sales in the second half of the year, he says. "Everyone is assuming PC demand will be strong in the second half, but there is nothing hard and guaranteed."

Mischou is not surprised that investors have sold off the stock because it had jumped 110% between Feb. 22 and March 20. On Tuesday, it fell 12% to close at 119 1/4, and it lost an additional 2.5% in after-hours trading after the news. Bottom line? He's not surprised by the Micron surprise.

So does the Street ever call Micron right? Says Kipp Bedard, Micron's vice president of corporate affairs: "No."