Spero Therapeutics, Inc. / Dividends

Declaration date	Ex date	Record date	Payment date	Amount
March 30, 2010			April 11, 2010	$0.01
June 29, 2010			July 12, 2010	$0.01
September 29, 2010			October 11, 2010	$0.01
December 13, 2010			December 31, 2010	$0.01
March 22, 2011			April 4, 2011	$0.01
June 13, 2011			July 8, 2011	$0.01
September 14, 2011			October 5, 2011	$0.01
December 12, 2011			January 5, 2012	$0.01
March 20, 2012			April 4, 2012	$0.01
June 13, 2012			July 6, 2012	$0.01
September 17, 2012			October 5, 2012	$0.01
December 17, 2012			January 7, 2013	$0.01
March 20, 2013	March 21, 2013	March 22, 2013	April 5, 2013	$0.015
June 12, 2013	June 13, 2013	June 14, 2013	July 5, 2013	$0.015
September 17, 2013	September 18, 2013	September 19, 2013	October 7, 2013	$0.015
December 17, 2013	December 18, 2013	December 19, 2013	January 6, 2014	$0.015
March 19, 2014	March 20, 2014	March 21, 2014	April 7, 2014	$0.015
June 18, 2014	June 19, 2014	June 20, 2014	July 7, 2014	$0.015
September 17, 2014	September 18, 2014	September 19, 2014	October 7, 2014	$0.015
December 17, 2014	December 18, 2014	December 19, 2014	January 6, 2015	$0.015
March 18, 2015	March 19, 2015	March 20, 2015	April 7, 2015	$0.015
June 17, 2015	June 18, 2015	June 19, 2015	July 7, 2015	$0.015
September 16, 2015	September 17, 2015	September 18, 2015	October 7, 2015	$0.015