Dimensional Fund Advisors has unloaded some of its holdings in Hornbeck Offshore Services and GulfMark Offshore.

The Austin, Texas-based investment firm told the US Securities and Exchange Commission (SEC) that it now controls nearly 2.69 million shares in Hornbeck, a New York-listed offshore vessel owner.

That represents a 7.5% stake worth $19m at today’s prices.

Dimensional last reported in November that it owned just over 3 million shares, or 8.5%,