TOKYO, Jan 22 (Reuters) - The Nikkei stock average eked out modest gains on Wednesday, with Tokyo Steel Manufacturing Co Ltd jumping after a robust earnings report. The Nikkei ended 0.2 percent higher at 15,820.96 after trading as low as 15,631.41 following a BOJ decision to keep monetary policy steady. A trader said some investors had been hoping that the BOJ might further ease this time. The BOJ also maintained its upbeat inflation forecasts, suggesting that no imminent monetary easing is on the horizon as the country's economic recovery broadens. The broader Topix index was up 0.3 percent at 1,299.63, with 2.66 billion shares changing hands, the most this week. The JPX-Nikkei Index 400, a recently introduced gauge comprised of companies with a high return on equity and robust corporate governance, added 0.3 percent to 11,728.57. Tokyo Steel, an electric furnace steelmaker, climbed 5 percent after returning to profit for the first ninth months of the business year on firm domestic demand and cost cuts. Peer Kyoei Steel Ltd gained 3.2 percent and Tokyo Tekko Co Ltd added 1.5 percent.