sell now or rent for year than sell???

would you plan to live there (or buy a similar apartment) when you return in two years? If so, I wouldn't think it's worth the transactions costs of selling only to rebuy so quickly. If the question is sell now or rent and sell in 1-2 years, it's a question of whether you want to speculate on real estate over the next couple years (while getting the relatively low rental returns that accompany NYC real estate).

Unless you are coming back to live in the same apartment - my 2 cents would be to sell now. Unless you can rent to cover your carry costs while in London (which these days would be unlikely) then you would have to make up that loss when you sold next year. Further - I don't see a big upswing in prices in one year that would justify holding out. (For complete disclosure - I'm a little bit of a bear.) On the other hand, JohnDoe is right - if you are a speculator and willing to gamble - go ahead and hold.

A lot also depends on how 'rentable' the apartment is. Is it near transportation? I'm assuming relatively so, from what you describe. Is it a studio? 1-bed? 2-bed? Also--what are your monthly carrying costs (don't forget to include insurance)? Do you think you will be able to at least break even if you sublet the place? Do some research on area rents/sublets in comparable buildings to get an idea.

As a previous poster mentions, if you plan to seek the same type of apartment when you return to NYC, do you really want to go through the time, effort and cost of purchasing for a second time in four years?