Answer:
The balance of trade will not change but the balance of payment will improve.
Step-by-step explanation:
A balance of trade is defined as the difference between country's export and import value during a given period of time.
A balance of payment can be defined as a statement which keeps record of all the monetary transaction, that are made between the country's resident and rest of the world during a specific period of time.
Purchase of U.S government securities by Japanese insurance company will surely improve the balance of payment from the U.S perspective but the balance of trade with Japan is not likely going to change.