SINGAPORE, Sept 14 (Reuters) - Grab, Southeast Asia"s biggest ride hailing-to-food delivery group, lowered its full-year forecasts on Tuesday, citing renewed uncertainty over pandemic-related movement restrictions despite encouraging vaccination rates in the region. Singapore-based Grab also said in a statement that it was making progress on its record merger deal agreed with U.S. special-purpose acquisition company (SPAC) Altimeter Growth Corp (AGC.O) earlier this year. And it reiterated that the deal, worth nearly $40 billion, is expected to be completed in the fourth quarter. L1N2M609X Grab, which has operations across eight countries and more than 400 cities in a region of 650 million people, said it expects to report group-level adjusted net sales of $2.1 billion to $2.2 billion, versus an expected $2.3 billion announced in April. SINGAPORE, Sept 14 (Reuters) - Grab, Southeast Asia"s biggest ride hailing-to-food delivery group, lowered its full-year forecasts on Tuesday, citing renewed uncertainty over pandemic-related movement restrictions despite encouraging vaccination rates in the region. Singapore-based Grab also said in a statement that it was making progress on its record merger deal agreed with U.S. special-purpose acquisition company (SPAC) Altimeter Growth Corp (AGC.O) earlier this year. And it reiterated that the deal, worth nearly $40 billion, is expected to be completed in the fourth quarter. L1N2M609X Grab, which has operations across eight countries and more than 400 cities in a region of 650 million people, said it expects to report group-level adjusted net sales of $2.1 billion to $2.2 billion, versus an expected $2.3 billion announced in April. It also forecast a group-level adjusted EBITDA loss of $0.7 billion to $0.9 billion for this year compared with a previously projected EBTIDA loss of $0.6 billion. "Grab"s full-year 2021 outlook anticipates an extension of partial and complete lockdowns throughout several countries where Grab operates as a result of the continuing spread of COVID-19," the company said. Grab"s second-quarter adjusted net sales jumped 92% to $550 million while its adjusted EBITDA loss rose 4% to $214 million. Grab said its quarterly total gross merchandise value (GMV), a metric used to measure transaction volumes, jumped 62% to a record $3.9 billion. GMV for deliveries grew 58% to $2.1 billion, while GMV for mobility rose 93% to $685 million.Our deliveries business continues to outperform and is growing rapidly, with the addition of new offerings such as GrabMart and GrabSupermarket, and we expect to continue investing heavily in this segment," Peter Oey, Grab"s chief financial officer, said.