13. Business Segment Information

The Company reports its financial results in two reportable business segments: AMSC Power Systems and AMSC Superconductors.

AMSC Power Systems produces a broad range of products to increase electrical grid capacity and reliability, supplies electrical systems used in wind turbines, provides power electronic products that interconnect wind farms and solar power plants to the power grid, licenses proprietary wind turbine designs to manufacturers of such systems, provides consulting services to the wind industry, and offers products that enhance power quality for industrial operations.

AMSC Superconductors manufactures high temperature superconductor (HTS) wire and coils; designs and develops superconductor products, such as power cables, fault current limiters and motors; and manages large-scale superconductor projects.

As described in Note 2, "Restatement," the Company's unaudited condensed consolidated financial statements included in the Original Form 10-Q for the quarterly period ending September 30, 2010 have been restated. Accordingly, the Company has restated operating results for its business segments for the three and six months ended September 30, 2010. The operating results for the two business segments are as follows (in thousands):

	Three months ended			Six months ended
	September 30,			September 30,
	2010		2010
	(Restated)	2009	(Restated)	2009
Revenues:
AMSC Power Systems	$95,084	$71,791	$190,012	$142,487
AMSC Superconductors	2,989	2,881	5,271	5,185
Total	$98,073	$74,672	$195,283	$147,672


	Three months ended		Six months ended
	September 30,		September 30,
	2010		2010
	(Restated)	2009	(Restated)	2009
Operating income:
AMSC Power Systems	$23,977	$19,866	$49,462	$35,261
AMSC Superconductors	-6,533	-5,647	-12,444	-11,144
Unallocated corporate expenses	-4,364	-3,889	-7,858	-7,396
Total	$13,080	$10,330	$29,160	$16,721

The accounting policies of the business segments are the same as those for the consolidated Company, except that certain corporate expenses which the Company does not believe are specifically attributable or allocable to either of the two business segments have been excluded from the segment operating income. Unallocated corporate expenses include stock-based compensation expense of $4.3 million and $3.9 million for the three months ended September 30, 2010 and 2009, respectively, and $7.8 million and $6.9 million for the six months ended September 30, 2010 and 2009, respectively. Unallocated corporate expenses for the three and six months ended September 30, 2009 included $0.1 million and $0.5 million, respectively, of restructuring charges related primarily to the closure of the Company's facility in Westborough, Massachusetts.

For the three and six months ended September 30, 2010, a substantial portion of the Company's revenues was recognized from one customer: Sinovel Wind Co., Ltd., a manufacturer of wind turbines based in China. Revenue to Sinovel represented 82% and 77% of total revenues for the three and six months ended September 30, 2010, respectively, compared to 76% and 65% for the three and six months ended September 30, 2009, respectively.

Total assets for the two business segments are as follows (in thousands):

	September 30,
	2010	March 31,
	(Restated)	2010


AMSC Power Systems	$254,623	$179,873
AMSC Superconductors	47,622	32,978
Corporate assets	162,632	187,333
Total	$464,877	$400,184