If you opted to sell immediately through the Halifax's own free dealing service - as nearly 2 million people have - it is now too late to change your mind. These sellers are guaranteed a minimum price of 415p a share, but in practice the figure is likely to be much higher.
If you opted to have your shares held in the Halifax Shareholder Account, you can sell your shares for free for the next 10 days. However, many people will want to hang on even if the price soars, and many of those will be considering putting their shares in a PEP - so making all profits and dividends tax-free.
There is no desperate hurry to PEP your shares. You can transfer the shares into a PEP at no charge any time during the next 42 days - mid- July is the deadline - and it may well be worth waiting a little in case Gordon Brown has his expected summer Budget and fiddles with PEPs.
If you are considering any PEP other than that of the Halifax (a particularly good idea for those getting other windfalls), you do need to get hold of a share certificate. If you opted for a certificate this should be on its way, but if your shares are in the Halifax Shareholder Account you will need to fill in a form arriving with details of your holding.
This is also the week for people due free shares from Norwich Union to decide whether they want a share certificate and whether they want to buy more shares at a discount.
If you want to ensure you have a certificate for your free shares in time for when dealings start on 16 June - in case you want to sell them immediately - and you don't want to buy any other Norwich shares, you need to return your form by Thursday - 5 June. Norwich won't be offering a free share-dealing service, so opting for a share certificate rather than the Norwich Share Account alternative seems sensible.
If you want to buy more shares you have until 10 June to get the form (and cheque) back. Windfall recipients are being offered a 25p discount, and the shares themselves are expected to do well when dealings start. People who buy extra shares should be looking at an immediate profit of at least 20 per cent on whatever they put in, maybe much more. Obviously there are risks - these are shares, after all. As I said last week, investors should only put in money they have - borrowing to invest in shares is a mug's game - and not their life savings either.
Whatever you decide, do return the form by 10 June - those who don't, risk facing a capital gains tax bill on their freebies.