OIL STS INTL INC

Ticker: OIS CUSIP: 678026105 Class: Common Stock

OBERWEIS ASSET MANAGEMENT INC/'s Holding History (CIK: 0000937886)

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

Q4 2018

Shares 17,750 Value ($000) $253 Avg Close $23.01 Range $13.20 - $34.66

Q3 2018

Shares 20,050 Value ($000) $666 Avg Close $32.65 Range $29.30 - $37.39

Q2 2018

Shares 23,550 Value ($000) $756 Avg Close $33.64 Range $25.25 - $38.95

Q1 2018

Shares 31,239 Value ($000) $818 Avg Close $28.65 Range $23.65 - $34.72

Q4 2017

Shares 33,349 Value ($000) $944 Avg Close $24.24 Range $20.23 - $29.15

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2018	17,750	$253	$23.01	$13.20 - $34.66
Q3 2018	20,050	$666	$32.65	$29.30 - $37.39
Q2 2018	23,550	$756	$33.64	$25.25 - $38.95
Q1 2018	31,239	$818	$28.65	$23.65 - $34.72
Q4 2017	33,349	$944	$24.24	$20.23 - $29.15