May 22 (Reuters) - National Australia Bank Ltd:
* Asx alert-open letter to shareholders on major bank tax-nab.ax
* Tax (from bank levy) could cost NAB approximately $350 million annually, or $245 million post tax
* "Actual cost will not be known until final legislation for tax has been passed and we can fully assess impact on NAB's business"
* "NAB will continue to strongly object to this tax"
* "No decisions have been made on how we will seek to manage cost of this new tax" Source text for Eikon: Further company coverage: