"Another leg down in oil prices could drive the U.S. market down as well," she said.
While U.S. stocks trade near all-time highs, U.S. crude oil futures have fallen more than 13 percent from above $51 a barrel last month to settle below $45 on Wednesday.
Earlier this month, Goldman Sachs Chief U.S. Equity Strategist David Kostin told clients there is a downside risk
of 5 to 10 percent in the short term due to geopolitical events. The firm has a year-end target of 2,100 for the S&P 500.
Subramanian kept her year-end target at 2,000 and her 10-year estimate at 3,500. BofAML slashed its forecast to 2,000 from 2,200 on February 12, a day after the so-called "Dimon bottom" when the index closed at 1,829.
With the S&P 500 expected to end this year about 43 points below its December 31, 2015 close, Subramanian recommends picking sectors. Her favorites are health care, telecom, real estate (which is set to become its own sector later this quarter) and tech. She's underweight financials (ex-real estate), consumer discretionary and materials.
During election years, "you want to own volatility," she said. The CBOE Volatility Index (.VIX) spikes above 24 on average in the month ahead of a presidential election, BofAML analysis showed.