| Type | Filed | Filer | Subject | Shares Owned | Percent Owned | |
|---|---|---|---|---|---|---|
| SC 13G/A | 2015-10-13 | EAGLE ASSET MANAGEMENT INC | NORTHWEST PIPE CO | 319,834 | 3.3% | EDGAR |
| SC 13G/A | 2015-08-04 | ROYCE & ASSOCIATES LLC | NORTHWEST PIPE CO | 1,009,093 | 10.6% | EDGAR |
| SC 13G | 2015-02-13 | Water Asset Management LLC | NORTHWEST PIPE CO | 483,999 | 5.1% | EDGAR |
| SC 13G/A | 2015-02-05 | DIMENSIONAL FUND ADVISORS LP | NORTHWEST PIPE CO | 780,183 | 8.2% | EDGAR |
| SC 13G/A | 2015-01-30 | BlackRock Inc. | NORTHWEST PIPE CO | 610,249 | 6.4% | EDGAR |
| SC 13G/A | 2015-01-26 | FIRST TRUST PORTFOLIOS LP | NORTHWEST PIPE CO | 749,675 | 7.9% | EDGAR |
| SC 13G/A | 2015-01-15 | ROYCE & ASSOCIATES LLC | NORTHWEST PIPE CO | 677,956 | 7.1% | EDGAR |
| SC 13G/A | 2015-01-09 | EAGLE ASSET MANAGEMENT INC | NORTHWEST PIPE CO | 1,030,661 | 10.8% | EDGAR |
| SC 13G/A | 2014-02-12 | VANGUARD GROUP INC | NORTHWEST PIPE CO | 283,215 | 3.0% | EDGAR |
| SC 13G/A | 2014-02-10 | DIMENSIONAL FUND ADVISORS LP | NORTHWEST PIPE CO | 763,628 | 8.1% | EDGAR |
| SC 13G/A | 2014-01-30 | BlackRock Inc. | NORTHWEST PIPE CO | 611,788 | 6.5% | EDGAR |
| SC 13G/A | 2014-01-14 | EAGLE ASSET MANAGEMENT INC | NORTHWEST PIPE CO | 1,201,635 | 12.7% | EDGAR |
| SC 13G/A | 2014-01-13 | ROYCE & ASSOCIATES LLC | NORTHWEST PIPE CO | 500,689 | 5.3% | EDGAR |
| SC 13G | 2014-01-08 | FIRST TRUST PORTFOLIOS LP | NORTHWEST PIPE CO | 516,222 | 5.5% | EDGAR |
| SC 13G/A | 2014-01-07 | HEARTLAND ADVISORS INC | NORTHWEST PIPE CO | 442,930 | 4.7% | EDGAR |
| SC 13G/A | 2013-03-05 | EAGLE ASSET MANAGEMENT INC | NORTHWEST PIPE CO | 1,297,748 | 13.8% | EDGAR |
| SC 13G | 2013-02-13 | VANGUARD GROUP INC | NORTHWEST PIPE CO | 500,103 | 5.3% | EDGAR |
| SC 13G/A | 2013-02-11 | DIMENSIONAL FUND ADVISORS LP | NORTHWEST PIPE CO | 731,287 | 7.8% | EDGAR |
| SC 13G/A | 2013-02-07 | HEARTLAND ADVISORS INC | NORTHWEST PIPE CO | 740,925 | 7.9% | EDGAR |
| SC 13G/A | 2013-02-05 | BlackRock Inc. | NORTHWEST PIPE CO | 571,605 | 6.1% | EDGAR |