STR Holdings Inc. (STRI), a supplier of materials for solar panels, will lose its biggest customer this quarter, First Solar Inc. (FSLR), and hired UBS AG (UBSN) to review its strategic options.

First Solar, the largest maker of thin-film photovoltaic panels, “will begin a transition away from STR in the first quarter of 2013,” the Enfield, Connecticut-based company said today in a statement.

First Solar accounted for about $39 million in sales for STR last year, according to the statement. Analysts expect STR to report total sales of $94.7 million for 2012. STR had $81.9 million in cash at the end of the year.

STR said its decision to hire UBS in December wasn’t related to losing First Solar.

To contact the editor responsible for this story: Will Wade at wwade4@bloomberg.net