LONDON (Reuters) - BHP's $39 billion bid will be the elephant in the room at Anglo American's Tuesday annual general meeting, with regulations meaning little can be said about the spurned offer.

The world's biggest listed mining group is considering making an improved offer for Anglo, a source familiar with the matter told Reuters on Saturday, after its initial takeover proposal was rejected last week.

Anglo shareholders would be keen to hear details of its strategy to respond to the bid at its AGM, which kicks off at 1000 GMT on Tuesday in London and online.

However, executives are unlikely to be able to discuss the company's plans due to restrictions in the UK Takeover Code, apart from a repeat of Anglo's statement rejecting the offer, a source familiar with the matter said.

Anglo rejected the offer on Friday as opportunistic, significantly undervaluing the miner and its future prospects.

"The company might use the opportunity to talk about other strategic combinations or disposals, but (it) will be difficult to do anything apart from the same speculation they have already engaged with," said analyst Ben Davis at Liberum.

In February, after Anglo reported a 94% plunge in annual profit and writedowns at its diamond and nickel operations, it announced a review of all its assets.

At the time, CEO Duncan Wanblad said the two assets dragging on Anglo's portfolio are its Anglo Platinum (PGMs) and diamonds businesses.

The Wall Street Journal said last week Anglo was considering selling diamond giant De Beers, of which it owns 85%.

Last week's bid included a spin out of Anglo's iron ore and platinum assets in South Africa, where BHP has no activities.