Green never forgave Houston for the failure of the Texas Railroad, Navigation and Banking Company. Still, he may have profited from the business venture despite its short-lived existence. In his Fiscal History of Texas, published in 1852, William Gouge maintained that one of the promoters of the company, whom he did not name, sold his interest in the business in New York for $30,000 worth of stores and supplies.29 Sam Houston repeated the charge some years later, specifically accusing Green of having sold his shares before the company defaulted on the bonus payment.30 Green denied the allegation, stating that he had lost $40,000 as a result of his interest in the company.31 However, he had traveled to New York in the spring of 1837, and with his brother, C. P. Green, purchased large quantities of dry goods as well as a 500-ton sailing vessel.32 It is not clear whether Green sold his own shares in the company or some of the capital stock available for public sale; in any case, New York customs collector Samuel Swartwout had occasion to meet with Green at this time and wrote to a friend in Texas that Green was "selling his bank shares fast." With assurances from Green that the promoters fully intended to comply with the terms of the charter, Swartwout himself purchased an interest in the company, and subsequently claimed to have been defrauded by Green and his brother when the company failed to meet its obligations.33

Green's open feud with the Houston faction would cost him his seat in the Second Congress. Although elected once again by the citizens of Bexar, this time to the Texas Senate, his political enemies contested the election on the grounds that he was not a resident of that county, and indeed had never resided there. Obliged to step down, Green devoted much of his time in the years that followed to business interests. He was one of the major developers of the town site of Velasco, which he hoped would become a thriving commercial port, competing with Galveston as a center of trade. He also served as president of a racetrack, the New Market course at Velasco, and kept a stable of horses that competed in the United States and Texas. In 1840 his thoroughbreds collected purses totaling $4,200.34

The victory of the anti-Houston candidates in the next presidential election (November 1838) revived Green's hopes for political patronage. Whatever lingering animosity President Lamar and Vice President Burnet harbored toward Green as a result of his earlier conduct seems to have been outweighed by their mutual hatred of Sam Houston. Once again, however, Green was to be disappointed. Acting upon the assumption that the Texas minister to Great Britain, James Hamilton, wished to return home, Lamar's secretary of state offered Green the job. The French minister to Texas, Dubois de Saligny, expressed his surprise that Green, "a complete nonentity but an intimate of the President," had been awarded such a prestigious post.35 The offer had to be withdrawn when Hamilton expressed his intention to remain at the Court of St. James.