The stock markets in the United States declined as investors become increasingly concern that Greece may not be able to reach a deal with its international creditors to prevent a default. Sign up for our free newsletter The leaders in the European Union conducted their first formal meeting regarding the possibility that Greece will default on its debt obligations, according to Reuters. A Greek government official denied reports that the leaders of the European Union discussed the possibility of a default. Greece is ready to submit its counter-proposals to its creditors and expects to reach a deal by June 18. The leaders of the European Union demanded Greece to present a proposal that would stabilize its debt. Some euro-zone officials told Reuters that they discussed a series of scenarios including Greece's potential default on a €1.6 billion payment due to the International Monetary Fund IMF by the end of this month. They also considered a scenario on a further extension of the current bailout program. The officials added that a scenario that a deal would be reached next weak was least likely to happen. Germany's Chancellor Angela Merkel urged Greece and its creditors to keep working on a deal. According to her, "Where there's a will there's a way, but the will has to come from all sides, so it's important that we keep speaking with each other." Karyn Cavanaugh, a senior market strategist at Voya Investment Management, commented, "Every time we think we're close to a deal with Greece there's some kind of monkey wrench. The more opaque the picture becomes with Greece, the more people opine on what the potential repercussions would be, and it's a little touch and go." Meanwhile, data showed that wholesale prices increased last month. The Department of Labor reported that the Producer Price Index for final demand increased 0.5% in May. A separate report showed that University of Michigan preliminary index of consumer sentiment in June increased to 94.6% from 90.7% last month.