Make loop display posts by alphabetical order

With this loop I am display single posts on an archive page. The posts are being sorted by having the category ‘Banks’. In addition to that how can i display them in alphabetical order. Ive tried using WP_Query, but cannot get it to work. It breaks my loop each time.

<h3>Banks & Credit Unions</h3>

		  <?php if ( have_posts() ) : while ( have_posts() ) : the_post(); ?>
		   	<?php if (in_category('Banks') ) { ?>

		   <li>
		   	<a href="<?php the_permalink() ?>">
		   	<img  src="<?php the_field('biller_logo')?>">
		   	<?php the_field('biller_name') ?>
		   </a>
		   </li>
		<?php } ?>
		  <?php endwhile; endif; ?>
</ul>