Kirby filed a shelf registration for shares it distributed as part of its deal to buy Stewart & Stevenson, a supplier of machinery for energy and marine industries.

Houston-Kirby made the $710m deal back in June to expand outside of its core transportation business.

Kirby chairman Joseph Pyne said at the time of deal that adding S&S "would dampen overall volatility in the business, and create a larger organisation at an opportune time, as the industry continues to recover from a deep downturn."