Shares of Applied Optoelectronics (AAOI - Get Report) are plunging Friday, down almost 21%, to $46.82. When accounting for Thursday's regular session losses, Applied Opto stock is down more than 24% over the past two days. 

In August, shares tanked, dropping to $65 from nearly $100 inside of one trading day after the company released its second-quarter results. After the Thursday close, shares were halted after the company announced preliminary fiscal third-quarter earnings. Results badly missed management's prior guidance and also fell well short of analysts' expectations.

Not surprisingly, analysts were out with several notes on Friday.

Cowen analyst Paul Silverstein cut his price target to $81 from $102. Despite the enormous fall, Silverstein's price target implies over 72% upside from current levels. He maintains his outperform rating and even though Applied Opto's result "fuels concerns" about its operating model, he says competitive pressures should remain at bay.

Needham's Alex Henderson also cut his price target, going to $75 per share from $115. He says Amazon.com, Inc. (AMZN - Get Report) seems to have "completely stopped buying 40G" product from Applied Opto, causing the severe miss on earnings and revenue for the quarter. However, he maintains his strong buy rating on the stock because its 100G business still seems upbeat.

Working our way down the price target list, Piper Jaffray's Troy Jensen lowered his to $63 from $87. The shortfall in sales shows the risk of having too much revenue come from one customer, that being Amazon in this case. He believes Amazon made up just 10% of sales last quarter, compared to 47% in the prior quarter. Applied Opto should have "significantly better" execution in 2018, particularly with its 100G business, he said. Jensen's target still implies 31% upside.

Lastly, Craig-Hallum analyst Richard Shannon cut his target to $42 from $80 as he downgraded the stock to hold. Shannon's target actually implies about 10.5% downside from current levels. 100G growth will be offset by the 40G headwinds that caused the earnings miss this quarter. Gross margins could come under pressure over the next one to two quarters, Shannon argued. He also cites increased competition from Intel (INTC - Get Report) .

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This article is commentary by an independent contributor. At the time of publication, the author had no positions in the stocks mentioned.