Ardmore Shipping's top shareholders are changing ranks according to US securities regulatory filings.

Among those are Boston Partners, which reported holding 1.67 million shares in the product tankers owner, amounting to a 5% stake.

Boston Partners, which has just over $99.2bn under management, focuses on value and small-capitalisation stocks in the US and abroad.

Boston, which has been an Ardmore shareholder since 2015, last reported holding 1 million shares in the company as of November 2017.

Another long-term holder, Donald Smith & Co, took the opposite tack trimming its stake to 3.063 million shares from 3.194 million shares reported last November. The deep value investing specialist had earlier held up to 3.36 million shares in the company, just over 10%.

Finally, FMR, the research arm of mutual fund giant Fidelity and the third largest asset manager in the world, reported a 7.9% stake in Ardmore, with just over 2.54 million shares. FMR had reported close to 2.9 million shares as of last March.