LONDON (Reuters) - Bitcoin regained its footing on Monday, having suffered its heftiest falls since early 2015 between Thursday and Saturday as investors sold the digital currency on worries about its future.<div><a href="http://feeds.reuters.com/~ff/reuters/technologyNews?a=cGyyRZvxq_0:yhNVsaXyYNE:yIl2AUoC8zA"><img src="http://feeds.feedburner.com/~ff/reuters/technologyNews?d=yIl2AUoC8zA" border="0" /></a> <a href="http://feeds.reuters.com/~ff/reuters/technologyNews?a=cGyyRZvxq_0:yhNVsaXyYNE:V_sGLiPBpWU"><img src="http://feeds.feedburner.com/~ff/reuters/technologyNews?i=cGyyRZvxq_0:yhNVsaXyYNE:V_sGLiPBpWU" border="0" /></a> <a href="http://feeds.reuters.com/~ff/reuters/technologyNews?a=cGyyRZvxq_0:yhNVsaXyYNE:-BTjWOF_DHI"><img src="http://feeds.feedburner.com/~ff/reuters/technologyNews?i=cGyyRZvxq_0:yhNVsaXyYNE:-BTjWOF_DHI" border="0" /></a></div><img src="http://feeds.feedburner.com/~r/reuters/technologyNews/~4/cGyyRZvxq_0" height="1" width="1" alt="" />