This, thus, makes the games Microsoft platform exclusives rather than Xbox One exclusives. Microsoft has used the branding "console launch exclusive" to refer to titles (such as "PlayerUnknown's Battlegrounds") that are timed or permanent exclusives to Xbox console hardware, but were already available on, or are planned to be available on PC. Microsoft initially imposed policies referred to as the "parity clause" on indie games, which required that the Xbox One version of a game be released at the same time as versions on other platforms. Phil Spencer stated that this rule was intended to ensure that Xbox One was a "first-class" platform by discouraging staggered releases. However, these policies resulted in some studios, such as Vlambeer (developer of "Nuclear Throne") choosing to negotiate console exclusivity with Sony instead, who proved to be more receptive to indie development. By July 2015, Microsoft had changed its policies in response to the criticism, with Spencer admitting that this policy was onerous on smaller studios. Spencer also stated that Microsoft was willing to work with studios to help make the Xbox launches of former timed exclusives "special in some way", so that customers are not simply purchasing "last year's game". Microsoft only publicized its sales figures during the first year after release. The last official figure was released in November 2014, with the company announcing in October 2015 that it would no longer publish sales figures for the system. On November 22, 2013, Microsoft confirmed that it had sold one million Xbox One consoles within its first 24 hours of being available. Based on approximately 102,000 shopping receipts tracked by InfoScout, 1,500 of which included a purchase of either a video game or a video game console, the Xbox One was the highest-selling console during the Black Friday sales period in the United States. On December 11, 2013, Microsoft announced that it had sold approximately 2 million units in its first 18 days on sale. On December 12, 2013, Microsoft announced it was the fastest selling console in the United States, based on NPD Group figures, however the NPD report clarified, "PlayStation 4 sales included an additional week within the November data month compared to Xbox One. When looking at sales on an average per-week basis, Xbox One led PS4. Keep in mind, however, that supply typically becomes constrained in the second week after launch." On January 6, 2014, Microsoft announced that approximately 3 million consoles had been sold worldwide in 2013. In their Q2 2014 earnings report on January 23, 2014, Microsoft announced that 3.9 million Xbox One units had been shipped worldwide.