BlueMountain Capital Management has lessened its stake in Overseas Shipholding Group (OSG) by nearly $2m.

The New York diversified alternative asset manager sold 515,491 units of the Samuel Norton-led company, taking ownership to 9.3% from 10.7%, according to a regulatory filing.

BlueMountain's divestiture in OSG is worth $1.74m, based on the shares closing at $3.37 Tuesday. The fund's OSG investment is currently valued at $26.5m.