Among those proposed as a potential suitor is Swiss giant Roche's US biotechnology partner Genentech, which has historic links with PDL as a pioneer in the field of humanised antibodies and pays royalties on sales of its blockbuster anticancer compounds Avastin (bevacizumab) and Herceptin (trastuzumab).
Indeed, last year PDL generated $184m (€130m) - up 42 per cent - in royalties from global sales of seven monoclonal antibodies.
Guidance for this year was for an expected $220m to $240m in royalty revenue.
Over 80 per cent of this royalty revenue came from Genentech and Roche and some analysts have estimated the figure is as high as 90 per cent.
Analysts are not ruling out Genentech being a possible marriage partner as a purchase would enable it to circumvent royalty payments on some of its biggest selling drugs.
Observers have suggested a purchase price for PDL in the region of $20-$30 per share - some are even optimistic for mid-$30s if the firm becomes the subject of a bidding war.
A price of $30 per share would take the total value of any deal to around $3.5bn and so the question remains as to whether Roche will see this as a good deal.
Some analysts don't think so, arguing that Genentech tends not to buy-in technology and has also recently acquired an antibody firm in the shape of Tanox.
That certainly hasn't stopped the share price scooting up this week though; it rose 9 per cent on 2 October to close at $23.24 with more than 17 million shares changing hands (the average is 3 million).
The rush dropped off yesterday as various analysts got cold feet - some saying the company has no premium value, others suggesting it received an offer earlier this year of $30 per share but knocked it back and it is unlikely to generate the interest now - but the stock still finished the day at $23.52.
Another frequently touted potential buyer is Biogen Idec, which already has an existing partnership with PDL for the multiple sclerosis treatment daclizumab and the cancer therapy volociximab, though Merck & Co, Eli Lilly and Schering-Plough have also been mentioned as possible suitors.
Meanwhile, some analysts' money is on an announcement being made next week, with speculation abounding that the share price will experience another boost tomorrow (October 5) in anticipation.
Watch this space.