Seattle-based conglomerate Saltchuk Resources has made an expected takeover offer for US-flag shipowner Overseas Shipholding Group (OSG), but one investor is calling the initial take-private bid "borderline insulting".

Saltchuk has been building a stake in Florida-based OSG since March 2020, when TradeWinds reported that it had bought 11.4m shares, or 13.3%, for about $26m in just over two months.

The US west coast outfit has now expanded the stake to 15.2m