Wire transfers are the best method. Costs can vary from $10 to $100 or more, depending on the banks and countries involved. There's rarely any saving using the same bank, although HSBC may have reduced charges if you have Premier accounts in both countries (for a one-off transaction, it may not be worth the effort to open an account).
However, that cost is insignificant compared to your possible losses on the currency exchange. Assuming your money is currently in Hong Kong Dollars (HKD), it will need to be converted to US Dollars (USD).
One place where it could be converted is at your Hong Kong bank. You'll get their retail rate. Make sure you are aware of the rate they will use, and any fees, in advance. Expect to pay around 2-3% from the mid-market rate (the rate you see quoted online, which doesn't fluctuate much for HKD-USD as the currencies are linked).
Another place where the currency could be converted is at your US bank. You really don't get any control over that if it arrives as HKD and is then automatically converted into your USD. The rate and fees could be quite poor, especially if it is a minor US bank that has to deal with anther bank for foreign currency.
For amounts of this size, it's worthwhile using a specialist currency conversion company instead. Currency Fair in Ireland is one. It's a peer-to-peer exchange that is generally the best deal (at least for the currency pairs I use). You wire the money to them, do the exchange on their site at a rate that is much closer to 0.5% from the midrate, then the money is transferred out by wire for a few dollars. Adds a few days to the process, but will possibly save you close to US$1000. Another established option is Currency Online in New Zealand.
There are probably also specialist currency exchange companies in Hong Kong. The basic rule is, don't let the banks exchange currencies at rates that suit them, use a third party that offers a better rate and lower fees.