The complaint was lodged in September by former Liberal MLA John van Dongen after he resigned from the party.
Van Dongen alleged Clark was in a conflict of interest over the sale of the railway because, although she didn't take part in the final decision, she failed to remove herself soon enough from key 2003 cabinet meetings where the matter was discussed.
Conflict of Interest Commissioner Paul Fraser asked Saskatchewan lawyer Gerald Gerrand to conduct an independent investigation into the matter.
In his report, issued on Wednesday morning, Gerrard found that Clark had acted properly and that, once she got advice from the conflict commissioner at that time about her then husband's involvement in the sale, she stepped aside.
Gerrard found the substance of van Dongen's complaint relied in part on information posted on the website of a local political blogger that further investigation revealed was not accurate.
In the end, Gerrand concluded there was no real basis for the complaint and Clark "was not in a position of conflict of interest or apparent conflict of interest."
NDP still promising public inquiry
The NDP has alreadypromised to hold a public inquiry into the sale if they win the May 14 provincial election, and on Wednesday the NDP justice critic Leonard Krog confirmed that is still the case.
"In as much as it's a nice little boost for the Premier, who has had nothing but bad news for weeks, it doesn't begin to answer, or wasn't intended to answer the fundamental question — was the sale of BC Rail corrupt?" said Krog.
Two former Liberal aides, Dave Basi and Bob Virk, did plead guilty to providing insider information to interested parties in the 2003 sale of BC Rail and receiving benefits for the information, and were sentenced to two years less a day in jail, in 2010.
But in January the B.C. Supreme Court ruled the province's auditor general does not have the right to see all the documents linked to the cost of the BC Rail trial and the decision to pay $6 million in legal fees for Basi and Virk.