TOKYO (Kyodo) -- Tokyo stocks trimmed earlier gains and ended mixed Tuesday as investors grew cautious ahead of the release of earnings from market heavyweight SoftBank Group later in the day.

The 225-issue Nikkei Stock Average fell 68.83 points, or 0.14 percent, from Monday at 50,842.93. The broader Topix index finished 4.16 points, or 0.13 percent, higher at 3,321.58.

On the top-tier Prime Market, the main gainers were air transportation and electric power and gas issues, while nonferrous metal and marine transportation shares were notable decliners.

The U.S. dollar briefly climbed to the mid-154 yen level in Tokyo but later retreated slightly and moved narrowly amid a lack of new trading incentives, dealers said.

At 5 p.m., the dollar fetched 154.18-19 yen compared with 154.10-20 yen in New York and 154.04-06 yen in Tokyo at 5 p.m. Monday.

The euro was quoted at $1.1561-1562 and 178.25-29 yen against $1.1552-1562 and 178.08-18 yen in New York and $1.1566-1567 and 178.17-21 yen in Tokyo late Monday afternoon.

The yield on the benchmark 10-year Japanese government bond fell 0.010 percentage point from Monday's close to 1.690 percent, as the debt was bought back following the previous day's sell-off. The yield rose to its highest level since June 2008 on Monday.

Stocks were initially supported by overnight gains on Wall Street amid growing expectations that the U.S. government will reopen soon, as prospects increased for Congress to pass a stopgap funding bill to end the shutdown, brokers said.

The benchmark Nikkei rose more than 600 points at one point in the morning, lifted by heavyweight chip and artificial intelligence-related stocks tracking a sharp rise in the tech-heavy U.S. Nasdaq index.

However, investors later turned cautious and locked in gains in chip shares ahead of technology and investment conglomerate SoftBank Group Corp.'s earnings report after the market closed Tuesday.

After the market closed, SoftBank Group reported a record net profit of 2.92 trillion yen ($18.97 billion) for the April-September period, nearly triple that from the same period the previous year.

"Investors likely wanted to see if the report shows solid figures, including returns from its active investments in the artificial intelligence and semiconductor fields, as hopes for AI growth helped lift the market recently," said Masahiro Ichikawa, chief market strategist at Sumitomo Mitsui DS Asset Management Co.