* BOJ could tweak communication, deposit system in March review * Policymakers keen to dispel view BOJ has run out of ammunition * Markets see deeper negative rates an unlikely policy option (Recasts with source confirmation, background on March review) TOKYO, Feb 10 (Reuters) - The Bank of Japan may consider taking steps at its March review that clarify to markets it has room to deepen negative interest rates to support the economy, said sources familiar with its thinking. The measures could include a change in communication or tweaks to the BOJ’s three-tiered reserves system that apply negative rates to a small portion of deposits parked at the central bank, three sources said on condition of anonymity. Such steps would dispel a dominant market view that the BOJ has run out of tools to ramp up stimulus and cannot deepen negative rates due to the cost of prolonged easing, they said. With the review still weeks away, there is no consensus within the BOJ on the final decision, the sources said. As the pandemic forces it to maintain a massive stimulus programme for a prolonged period, the BOJ plans to announce next month ways to make its tools more sustainable. BOJ officials, including Governor Haruhiko Kuroda, have said one of the key objectives will be to make its tools “nimble” so it can respond to future shocks in a timely way. “We must also maintain our commitment to achieve 2% inflation. Based on the commitment, we’ll be ready to lower nominal rates as needed,” BOJ Deputy Governor Masazumi Wakatabe said last week. Under a policy dubbed yield curve control, the BOJ guides short-term rates at -0.1% and 10-year bond yields around zero. Kuroda has consistently said deepening negative rates would be among options if the BOJ were to ease further. But many analysts say the threshold for taking the step is high because of the strain ultra-low rates is inflicting on commercial banks’ profits. (Reporting by Leika Kihara; Editing by Catherine Evans and Kim Coghill)