Private equity firm Sycamore is buying office supplies chain Staples for $6.9 billion. Reports in April said Staples was in deal talks, less than a year after it dropped a $6.3 billion merger with Office Depot because of opposition from antitrust regulators. Hundreds of inventors have flocked to Walmart’s headquarters in Bentonville, Ark., to find out if the country needs a few more secret sauces, prettier mouse pads or “instant hair gel” packets for the on-the-go clubber. The 500 businesses selected to take part in Walmart’s fourth annual “Open Call” on Wednesday have already been offered spots on the company’s online portals, as it battles Amazon for billions of dollars in revenue. Visits with Walmart’s marketing team, though, could land any number of entrepreneurs some shelf space in nearly 4,700 brick-and-mortar stores. “It’s a high-stakes game,” Scott Hilton, Walmart’s executive chief revenue officer for e-commerce, said as the meeting opened. Through its portal, it gives any would-be sellers step-by-step online guidance on how to receive and fulfill orders. With auditions, Walmart does it differently, and its physical stores handle a finite number of goods. Bringing potential sellers to headquarters for Wednesday’s crash course in marketing reinforces Walmart’s path to making money. The Federal Reserve has given the green light to all 34 of the biggest banks in the U.S.