If existing British owners rushed to sell, accepting prices under market value just to get out, this would have a negative impact on the market.

cap rate would be negative, still buying it?

@Allie Reeves if your in a negative cash flow scenario it's time to sell.

I  don't mean to be negative, I just want you to attain enough money to finish the deal with the least stress possible.Do you by chance own a home that you can have enough equity in that you can use a home equity line of credit (HELOC) that you can borrow from?  

My team and I have crunched a ton of data on the city, and it never made sense to me why people still buy NYC properties for investing; albeit you do benefit from price stability and perhaps even tax reasons given you'll be negative cash flow most of the time. 

Future mortgage rates will probably be even higher than they are currently, and may have a negative impact on any real estate investments as cost of funds increase - mostly those with ARMs or are looking into a mortgage in the future.

It could quickly turn a small positive cash flow to a negative.

The combination of large mortgage payment and reduced rental income typically results in neutral or negative Cash Flow for the first year you own the property.  

Currently, I have negative cash flow in an appreciation market (Hawaii) so I'm looking to turn that into monthly cash flow in order to make a career change.

For me, I'm always trying to find the negative in a property to talk myself out of it.