[3][2] From 1999 until 2000, Costa served as a law clerk to Judge A. Raymond Randolph on the U.S. Court of Appeals for the District of Columbia Circuit.

[3][2] Likely Costa's highest-profile prosecution in his six years as a federal prosecutor was the case against convicted Ponzi schemer Allen Stanford, who was indicted in 2009.

"[4] In February 2011, Stanford sued Costa and his fellow prosecutor Paul Pelletier, along with several employees of the Securities and Exchange Commission and the Federal Bureau of Investigation, complaining of "abusive law enforcement" and seeking $7.2 billion in damages.

[6] In March 2012, Stanford was found guilty on 13 of 14 counts including fraud, obstructing investigators and conspiracy to commit money laundering.

[7] In July 2011, Texas's two Republican senators, John Cornyn and Kay Bailey Hutchison, sent a letter to President Barack Obama,[8] recommending that he nominate Costa to the vacant seat on the United States District Court for the Southern District of Texas that had been created when Judge John David Rainey took senior status in June 2010.

[2] On December 19, 2013, President Obama nominated Costa to a seat on the United States Court of Appeals for the Fifth Circuit vacated by Fortunato Benavides, who assumed senior status on February 3, 2012.

2019), a ruling that struck down the Federal Housing Finance Agency as a violation of the separation of powers and was affirmed by the Supreme Court in Collins v. Yellen.