Anglo American's chair is gathering feedback from top shareholders on BHP's $39 billion bid, labelled "opportunistic" and "undervaluing" by Anglo. Shareholders expressed doubts and support at the AGM, but questions are limited due to takeover regulations. BHP may improve its offer by May 22, amid Anglo's asset review and shareholder sentiments..Sign up for your early morning brew of the BizNews Insider to keep you up to speed with the content that matters. The newsletter will land in your inbox at 5:30am weekdays. Register here..SOURCE: REUTERS.By Clara Denina and Eric Onstad.LONDON (Reuters) -Anglo American's chair will meet its top 30 shareholders to hear views on BHP's $39 billion bid for the miner, he told an annual general meeting on Tuesday, where he was restricted from discussing the spurned offer by takeover regulations. .___STEADY_PAYWALL___.Anglo rejected the offer on Friday, saying it was opportunistic, significantly undervaluing the company and its future prospects..Some questions and comments from shareholders echoed broader concerns about the price and nature of BHP's bid.."To what extent can you survive if you reject the offer?" one shareholder asked..Chair Stuart Chambers said business was proceeding as usual, having asked shareholders at the start of the AGM for no questions about the bid because the company couldn't respond under restrictions applied by the UK Takeover Code. .The world's biggest listed mining group BHP is considering making an improved offer for Anglo, a source familiar with the matter told Reuters on Saturday.."It's not the board that decides, but you," Chambers added. .Another shareholder thanked Chambers for rejecting "the comedy offer" from BHP, saying he valued the company at 41 pounds a share..Under UK takeover rules, BHP has until May 22 to come back with a formal offer after the group said last week it would pay 25.08 pounds per Anglo share, a premium of 31% from the previous day's close..Anglo shares were down 3.5% at 26.53 pounds on Tuesday..In February Anglo announced a review of all its assets, after reporting a 94% plunge in annual profit and writedowns at its diamond and nickel operations..At the time, CEO Duncan Wanblad said the two assets dragging on Anglo's portfolio were its Anglo Platinum and diamonds businesses..A source told Reuters last week that Anglo was looking for partners for its De Beers diamonds business, which is among the assets BHP has said it would review after completion of any deal..Last week's bid included a spin out of Anglo's iron ore and platinum assets in South Africa, where BHP has no activities.  .Read also:.Activist-led Elliott builds $1bn stake in Anglo American amid BHP takeover bid BHP's proposed Anglo American takeover: The complexities of a mega-merger FT: How Anglo American turned into prey.(Reporting by Clara Denina and Eric Onstad; Editing by Veronica Brown, Alexander Smith and Jan Harvey)