An opinion out of the state Office of Information Practices last week settles what should have been obvious in the first place: When the state asks private individuals and companies to help pay for official business, such as trade and promotion trips, the identities of the businesses and the amounts they contribute should be made public.

Such disclosure increases public confidence by working to ensure that there is no tradeoff of favors or special treatment in exchange for such help. That transparency underscores a basic difference between the activities of a taxpayer-supported government and a private entity.

The administration of Gov. Linda Lingle has been soliciting private support for its successful trade missions to Asia for some time. But it has been reluctant to reveal the names of the donors, how much they gave and what precisely they got in return.

There's no doubt the businesses gave willingly, to both help the state and their own economic interests. But when they lash up with a taxpayer-supported endeavor, an obligation for an extra level of openness attaches.

The OIP opinion, after an inquiry from The Advertiser, said that whatever privacy interests the businesses might have had were clearly outweighed by the public's right to know.

The administration says it will fully comply with the opinion in the future. That's the right approach, but it should not have taken a formal OIP opinion to make it so.