Source: Sharecast
"Discussions with H.B. Fuller are ongoing and there can be no certainty that a firm offer will be made, nor as to the terms on which a firm offer might be made," the company said in a brief statement.
Under UK takeover rules, H.B. Fuller has until 1700 BST on 18 June to either announce a firm offer or walk away.
In a separate statement, the US company said: "H.B. Fuller has been a successful and disciplined acquiror focused on high growth markets with differentiated technology. H.B. Fuller continues to explore opportunities in its M&A pipeline including, but not limited to, other assets in the medical adhesives market."
Confirmation of the approach from H.B. came just days after private equity firm TA Associates said it was not planning to make an offer for the company.
AMS said at the time that it "remained confident" in its standalone prospects and strategy "which it believes will continue to deliver sustainable growth and value creation for shareholders".
At 1607 BST, AMS shares were up 5.4% at 222.94p.
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