(Reuters) - Home Depot Inc HD.N announced a $15 billion share buyback plan on Wednesday and said it would invest in improving its stores to hit a $120 billion annual sales target in the next three years.

The retailer’s shares fell 1.4 percent to $180.22 on the New York Stock Exchange as its latest buyback target pointed to a slowdown in the pace of repurchases.

The largest U.S. home improvement store chain said it expects to buy back $12.5 billion over the next three years, compared with the $8 billion it plans to buy for the year ending January 2018. It plans to buy $2.1 billion of shares in the current quarter.

Home Depot is riding a multi-year recovery in the U.S. housing market and has benefited from reconstruction and repair work after Hurricanes Irma and Harvey struck the United States in August and September.

But it also must contend with growing competition from online and brick-and-mortar rivals, so it plans to speed up investment in its in stores, employees, deliveries and online business.

“The retail landscape is changing at unprecedented rates and we plan to invest for the future to address the evolving needs of our customers,” Chief Executive Officer Craig Menear said in a statement.

The Atlanta-based company said it would invest in making check-out faster for customers as well as wages and scheduling for employees. It would also change its merchandise more frequently and make it easier for customers to navigate its giant stores by adding digital signs.

The company is doubling its total investment spending over three years, which puts a limit on its profitability expansion and the shares it can buy back, which could be weighing on investor appetite for the stock today, Edward Jones analyst Robin Diedrich said.

The company on its investor day call sought to allay concerns about limits on deductions for mortgage interest proposed under the Republican U.S. tax overhaul, a factor that may curb the appetite for new homes.

There was no empirical evidence to suggest that tax deductibility influences the rate of home ownership, Home Depot’s Chief Financial Officer Carol Tomé said, because only 5 percent of mortgages are more than $500,000, the proposed cap for tax deductions.

Its target range for sales for the year ending January 2021 were for between $114.7 billion and $119.8 billion, compared with this year’s goal of $100.6 billion.

Home Depot said the new buyback program would replace its previous authorization of $15 billion set in February.

Home Depot’s shares have climbed about 36 percent this year.