PROTO LABS INC

Ticker: PRLB CUSIP: 743713109 Class: EQTY

Robeco Institutional Asset Management B.V.'s Holding History (CIK: 0001418773)

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

Q4 2018

Shares 4,187 Value ($000) $472 Avg Close $123.33 Range $101.03 - $163.03

Q3 2018

Shares 4,187 Value ($000) $677 Avg Close $141.47 Range $115.95 - $166.60

Q2 2018

Shares 4,187 Value ($000) $498 Avg Close $122.45 Range $111.20 - $136.40

Q1 2018

Shares 4,187 Value ($000) $492 Avg Close $113.00 Range $100.05 - $126.95

Period	Shares	Value ($000)	Average Close	Price Range
Q4 2018	4,187	$472	$123.33	$101.03 - $163.03
Q3 2018	4,187	$677	$141.47	$115.95 - $166.60
Q2 2018	4,187	$498	$122.45	$111.20 - $136.40
Q1 2018	4,187	$492	$113.00	$100.05 - $126.95