WASHINGTON – With just one day left before President Joe Biden departs for a week of summits in Europe, Democrats in Congress were still deep in negotiations Wednesday over several key pieces of the president’s social safety net and climate bill.

However, there were visible improvements in at least one area: taxes.

Three Democratic Senators presented Tuesday’s plan to impose 15% on the corporate income book. It would be applicable only to those companies who have earned more than $1 million in three consecutive years.

It quickly received approval from Kyrsten Silena, Arizona, and Joe Manchin, West Virginia.

Even though Democrats unified around the 15% minimum corporate income tax, there were two additional tax reforms that appeared headed towards the scrap heap.

CNBC’s Kayla Tausche reports Wednesday that a plan for banks to report cash flow data to the IRS on accounts with over $10,000 of non-wage deposit was not under consideration. She cited three people familiar with the matter.

A late-breaking plan to annually tax the unrealized market gains of the very richest Americans – people reporting more than $100 million of income or holding more than $1 billion in assets – also appeared to be on shaky ground Wednesday. Manchin said that he believed the plan was “convoluted.”

After Sinema’s mid-October announcement that she wouldn’t support an old plan to raise corporate income taxes and the highest individual tax bracket rates to generate revenue, potential sources of revenue for paying the bill were brought to the forefront.

Democrats must have all 50 senators present in their caucus for any bill to be passed, and Sinema’s announcement has left the party reeling.

However, while tax and other “pay-fors,” continue to be a problem for some Democratic legislators, there are still questions regarding the benefits that the bill will actually bring.

The disagreements revolved around the preservation of certain benefits in Biden’s original social spending plan, like federal paid family leaves and Medicaid expansion. However, the bill’s overall cost was kept below $2 trillion.

Manchin is against several proposed benefits expansions and continued to exercise outsized influence on Wednesday over the negotiations.

Manchin said that his opposition to Medicare expansion and Medicaid expansion is motivated by his concern over the long-term viability of both programs.

Medicaid offers health insurance for over 75 million Americans who are low-income or vulnerable. Medicare provides health coverage to 60 million people older than 65.

Manchin is also opposed to a popular proposal to establish a system that would administer and finance a federal family leave program for all employees.

Biden’s 2020 campaign promise to reduce the burden of financial hardship on families was central.

Manchin views it as an unnecessary benefit for the government and raises overall costs of the legislation.

You can check back frequently for more updates.

CNBC’s Kayla Tausche reported.