POWER SOLUTIONS INTL INC

Ticker: PSIX CUSIP: 73933G202 Class: Common Stock

ESSEX INVESTMENT MANAGEMENT CO LLC's Holding History (CIK: 0000201772)

Note: Option positions (PUT/CALL) are excluded.

Q4 2013

Shares 37,032 Value ($000) $2,781 Avg Close $65.56 Range $52.30 - $78.96

Q3 2013

Shares 12,078 Value ($000) $714 Avg Close $48.66 Range $33.00 - $59.26

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2013	37,032	$2,781	$65.56	$52.30 - $78.96
Q3 2013	12,078	$714	$48.66	$33.00 - $59.26