Exchange rate quoting conventions

According to the last errata for CFA Level II,

http://www.cfainstitute.org/Eratta/2013_level_II%20_errata_as_of_29_october.pdf

the convention is /£ or £: for dollars to the pound, but Google Finance quotes this rate as

British Pound Sterling (£) / US Dollar ($) (GBPUSD)

and Yahoo! Finance quotes the rate as

GBP/USD (GBPUSD=X)

So these are completely wrong unless they use a completely different convention for the three-letter trading symbols, because I’m suspecting that

  • $/£
  • £:$
  • GBP/USD
  • GBPUSD
  • GBP:USD

all quote the same rate, although it seems ridiculously inconsistent to me.

EDIT: I know it’s inconsistent, because “GBP/USD” on the popular search engine websites is what the CFA curriculum refers to as “USD/GBP”. Somebody care to help me out here?

CFA errata text:

“There are a variety ways of quoting foreign exchange rates: to or per £ = /£ = £: . The quote £: is equivalent to a quote of $/£. Authors use the two different methods of quoting currency exchange rates to ensure readers develop familiarity with both.” I think they are saying that both can quote both ways. You typically see GBP/USD = ~1.6. The Sterling is stronger and usually on top. You can also use USD/GBP ~.625. But I think they are really just saying that it can be a “/” or a “:”, and I guess the “:” reverses the order (although I never knew that).

To clarify, my interpretation, which could be incorrect, is that they are saying that GBP/USD = USD:GBP.

That’s what yahoo, google etc. are saying.