Hawkeye Company’s balance sheet reported, under the equity method, its long-term investment in Raven Company for comparative years as follows:

Investment in Raven Company stock (in millions):
December 31, 20Y5 - $264
December 21, 20Y6 - $281

In addition, the 20Y6 Hawkeye Company income statement disclosed equity earnings in the Raven Company investment as $25 million. Hawkeye Company neither purchased nor sold Raven Company stock during 20Y6. The fair value of the Raven Company stock investment on December 31, 20Y6, was $310 million.

Explain the change in Investment in Raven Company Stock from December 31, 20Y5, to December 31, 20Y6.