(Adds possible Shire acquisitions)
LONDON, April 29 (Reuters) - Shares in London-listed drugmaker Shire Plc jumped nearly 6 percent on Tuesday after Reuters reported that Botox-maker Allergan Inc was preparing a new takeover approach.
Allergan itself is facing an unsolicited bid from Valeant Pharmaceuticals International Inc, and a bid for Shire, whose market value is more than $33 billion, would underscore how keen the U.S. dermatology drugmaker is to stay independent.
Representatives at Allergan and Shire declined to comment.
Citi analyst Peter Verdult said Shire could be attractive to Allergan given the London-listed company's strong sales of high-margin drugs for treating rare diseases. The transaction would also offer significant cost and tax savings.
Getting a deal done, however, would depend on the premium Allergan is willing to pay for Shire and the readiness of Shire shareholders to receive a large part of the payment in equity, he said.
Valeant teamed up with activist investor Bill Ackman this month to make a $47 billion offer for Allergan. But Allergan has been reluctant, partly because of Valeant's reputation for cutting costs and spending little on research and development.
Allergan had held talks in recent months with Shire about a potential takeover, but they did not pan out, Reuters reported last week.
One person familiar with the matter said Allergan could make a new approach within the next few days.
Shares of Shire were up 5.8 percent by 1221 GMT.
Shire holds its annual meeting in Dublin on Tuesday and will report first-quarter results on May 1.
It could also decide to remain independent and pursue more acquisitions, especially in speciality drugs, said several bankers familiar with Shire's strategy. Biopharma firm Thrombogenics, which specialises in ophthalmology, could be a good fit for Shire, the bankers said.
Shire has grown to its current 19.3 billion pound ($32.4 billion) market capitalisation mainly through acquisitions and last year bought rare disease firm Viropharma for $4.2 billion.
At its AGM on Tuesday it was due to discuss the possibility of pushing its borrowing capacity from its current $4 billion to $12 billion to reflect the company's growth.
Any transaction would add to a frenzy of deal-making in the healthcare sector. Deals totalling more than $153 billion have been struck so far this year, the highest year-to-date level since Thomson Reuters began tracking data.
A takeover of Shire, which is based in Dublin, would also play to an increasingly popular trend that is driving M&A in healthcare and other sectors - it could help lower Allergan's tax rate.
In a process known as inversion, U.S. drugmakers seek to relocate their headquarters to countries with lower tax rates, as Pfizer hopes to do with AstraZeneca . ($1 = 0.5950 British pounds) (Reporting by Ben Hirschler, Anjuli Davies and Sophie Sassard; Editing by Louise Ireland and Susan Fenton)