Japan's Nikkei flat, banks and property firms weigh

(Updates to midmorning)

TOKYO, June 11 (Reuters) - Japan's Nikkei stock average was flat after giving up early gains on Wednesday, weighed down by banks such as Mizuho Financial Group (8411.T) after a megabank downgrade and property firms sliding on growing worries about the sector. Mitsubishi Corp (8058.T) and other trading firms fell after oil dropped sharply on Tuesday, with energy-linked shares also taking a hit.

The benchmark Nikkei .N225 gained 5.17 points, rising 0.04 percent to 14,026.34. The broader Topix was down 0.4 percent at 1,377.51. (Reporting by Elaine Lies)